Multifunctional viscosity index improver derived from polyamine containing one primary amine group and at least one tertiary amine group and degraded ethylene copolymer

ABSTRACT

A multifunctional viscosity index improver for lubricating oils comprising reaction product of: 
     (i) (a) degraded ethylene-alpha-olefin copolymer obtained by degrading undegraded copolymer of ethylene and at least one other alpha-olefin monomer, said undegraded copolymer comprising intramolecularly heterogeneous copolymer chain containing at least one crystallizable segment of methylene units and at least one low crystallinity ethylene-alpha-olefin copolymer segment, wherein said at least one crystallizable segment comprises at least about 10 weight percent of said copolymer chain and contains at least about 57 weight percent of said copolymer chain and contains at least about 57 weight percent ethylene, wherein said low crystallinity segment contains not greater than about 53 weight percent ethylene, and wherein said copolymer has a molecular weight distribution characterized by at least one of a ratio of M w  /M n  of less than 2 and a ratio of M z  /M w  of less than 1.8 and wherein at least two portions of an individual intramolecularly heterogeneous chain, each portion comprising at least 5 weight percent of said chain, differ in composition from one another by at least 7 weight percent ethylene; said degraded copolymer grafted with (b) ethylenically monounsaturated carboxylic acid material having 1 to 2 carboxylic acid groups or anhydride group to form grafted degraded ethylene copolymer; and 
     (ii) at least one polyamine containing one primary amino group and at least one tertiary amino group.

This application is a 37 C.F. R. 1.62 continuation of U.S. Ser. No.420,186, now abandoned, which was filed Oct. 12, 1989, now abandoned.

FIELD OF THE INVENTION

The present invention relates to nitrogen containing grafted degradedethylene copolymers useful as multi-functional viscosity index (V.I.)improver additives, e.g., viscosity index improvers-dispersants, foroleaginous compositions, particularly fuel oils and lubricating oils,methods for preparing said nitrogen containing grafted degraded ethylenecopolymers, and to oleaginous compositions containing these nitrogencontaining grafted degraded ethylene copolymers. More specifically theinstant invention relates to nitrogen containing grafted ethylenecopolymers comprising molecular weight degraded copolymers of ethyleneand at least one other alpha-olefin, said degraded copolymers beingobtained by degrading ethylene-alpha-olefin copolymers comprised ofsegmented copolymer chains with compositions which are intramolecularlyheterogeneous and intermolecularly homogeneous, grafted withethylenically unsaturated carboxylic acid material and reacted withpolyamine containing one primary amine group and at least one tertiaryamine group. The compositions of matter of the instant invention provideoleaginous compositions, particularly lubricating oil compositions,exhibiting improved low temperature viscometric properties compared tooleaginous compositions containing conventional nitrogen containinggrafted ethylene-alpha-olefin copolymers.

BACKGROUND OF THE INVENTION

It is known that the viscosity index of an oleaginous composition suchas lubricating oil can be increased or improved by incorporating thereincertain polymeric materials which function as viscosity index improvers.Known viscosity index improvers include polyisobutene and copolymers ofethylene and other hydrocarbon olefins. It is also known that theseviscosity index improvers can be grafted with grafting materials suchas, for example, maleic anhydride and the grafted material then reactedwith a polyamne or polyol to form multifunctional viscosity indeximprovers.

Generally, the polymeric materials useful as viscosity index improversare those having number average molecular weights of from about 15,000to about 250,000, preferably from about 20,000 to about 150,000.However, some of such polymers having this molecular weight range aredifficult to process, isolate and handle, or are relatively moreexpensive to produce than their higher molecular weight homologs.Therefore, with such polymers it is generally easier and more economicalto form their higher molecular weight homologs, for example those havingnumber average molecular weights of from about 30,000 to about 500,000,and then to degrade these high molecular weight polymers to the desiredmolecular weight.

It is known that olefin and di-olefin homopolymers and ethylene-α-olefincopolymers may be degraded, thereby reducing the molecular weightthereof. Such degradation is known to be accomplished, for example, byshear assisted oxidation of the polymers and copolymers in air in amechanical mixer, such as in an extruder, masticator, Banbury mixer,rubber mill, or the like, and by heating the polymers and copolymers,sometimes in the presence of air. one such degradation process, which isdescribed in U.S. Pat. No. 3,313,793, involves (a) the formation of asolution of a conjugated diene polymer, (b) combining therewith aperoxide and a copper source such as copper, a copper halide or a coppercarboxylate, (c) heating the resulting mixture in the substantialabsence of oxygen, and (d) recovering a diene polymer product having asubstantially reduced average molecular weight.

U.S. Pat. No. 3,332,926 relates to the thermal degradation ofpolyolefins, including ethylene-propylene copolymers, to producerelatively low molecular weight polymers which are useful, for example,as wax substitutes, blending agents, coating compositions and, ingeneral, in fields where hydrocarbon resins and waxes find utility. Theprocess described in that patent comprises mixing a crystalline startingpolymer with from 0.075% to 10% by weight of a metal salt of carboxylicacid and heating the mixture in an atmosphere which is substantiallyfree from oxygen to a temperature of about 275° C. to 450° C., until asubstantial reduction in the molecular weight of the polymer takesplace.

U.S. Pat. No. 3,316,177 discloses a functional fluid containing a sludgeinhibiting detergent comprising the polyamine salts of the reactionproduct of the maleic anhydride and an oxidized interpolymer ofpropylene and ethylene. The interpolymers from which the oxidized,degraded interpolymers are derived usually have molecular weights of atleast about 50,000. The interpolymers are oxidized and degraded byheating them at a temperature of at least about 100° C. in the presenceof oxygen or air. Such degradation usually is characterized by asubstantial reduction of the molecular weight of the interpolymer.

U.S. Pat. No. 3,345,352 relates to a catalytic process for the thermaldegradation of the polyolefins, including copolymers of ethylene andpropylene. The degradation process involves heating a mixture of acrystalline polyolefin and an oxide or carbonate of an alkali metal,alkaline earth metal, or certain selected transition metals such ascopper, iron, titanium, vanadium, etc. in an atmosphere substantiallyfree of oxygen to a temperature of from 275° C. to 450° C. for a minimumtime period of at least five minutes.

U.S. Pat. No. 3,687,849 relates to lubricants containing oil-solublegraft polymers derived from degraded ethylene-propylene interpolymers.The interpolymers from which the degraded polymers are derived usuallyhave a molecular weight of about 50,000-800,000, and the degradedinterpolymers are prepared by heating the interpolymer, or a fluidsolution of such interpolymer, in an inert solvent, at a temperature ofat least about 140° C. in the presence of oxygen or air. The degradationof the interpolymer is characterized by a substantial reduction of itsmolecular weight. A similar disclosure is set forth in U.S. Pat. No.3,687,905.

U.S. Pat. No. 3,769,216 relates to polymers which are produced byreacting a primary or secondary amine and a mechanically degraded,oxidized atactic ethylene propylene copolymer, and to automotivelubricating oils containing such polymers as antivarnish additives. Theethylene propylene copolymer is mechanically degraded in the presence ofoxygen and in the absence of any solvent in a closed vessel equippedwith shearing blades. A typical apparatus of this type is described as adevice containing counter-rotating helical blades and known as a"Brabender Torque Rheometer."

U.S. Pat. No. 4,089,794 discloses ethylene copolymers derived from about2 to 98 wt % ethylene, and one or more C₃ to C₂₈ α-olefins, for exampleethylenepropylene, which are solution-grafted with an ethylenicallyunsaturated carboxylic acid material, and thereafter reacted with apolyfunctional material reactive with carboxyl groups. The resultingpolymers are useful as dispersant additives for lubricating oils andhydrocarbon fuels, and as multifunctional viscosity index improvers iftheir molecular weight is above 10,000.

U.S. Pat. No. 4,113,636 discloses the mechanical degradation at elevatedtemperatures, and in the presence of air or oxygen-containing gas, ofcopolymers comprising about 68 to 80 mole % ethylene and one or more C₃-C₈ α-olefins to form an oxygenated-degraded polymer which is thenreacted with an amine compound. The resulting aminated polymers areuseful as viscosity index improving additives.

U.S. Pat. Nos. 4,074,033 and 4,201,732 relate to a process for improvingthe processability for high molecular weight neoprene polymers. Theprocess comprises treating a solution of the polymers in an organicsolvent with an organic peroxide, in the presence of oxygen, to reducethe molecular weight of the neoprene and to lower the viscosity of thesolution. The process may be conducted at room temperature with orwithout agitation, and an accelerator such as a cobalt salt or othertransition metal salt may be employed.

The concept of grafting high molecular weight ethylene and α-olefincopolymers, either degraded or undegraded, with acid moieties such asmaleic anhydride, followed by reaction with an amine to form acomposition useful as a multifunctional viscosity index improver, e.g.,viscosity index improver-dispersant, oil additive is also known and inaddition to being disclosed in some of the aforediscussed patents isalso disclosed, inter alia, in the following disclosures:

U.S. Pat. No. 3,316,177 teaches ethylene copolymers such asethylene-propylene, or ethylene-propylene-diene, which are heated toelevated temperatures in the presence of oxygen so as to oxidize thepolymer and cause its reaction with maleic anhydride which is presentduring the oxidation. The resulting polymer can then be reacted withalkylene polyamines.

U.S. Pat. No. 3,326,804 teaches reacting ethylene copolymers with oxygenor ozone, to form a hydroperoxidized polymer, which is grafted withmaleic anhydride followed by reaction with polyalkylene polyamines.

U.S. Pat. No. 4,089,794 teaches grafting the ethylene copolymer withmaleic anhydride using peroxide in a lubricating oil solution, whereinthe grafting is preferably carried out under nitrogen, followed byreaction with polyamine.

U.S. Pat. No. 4,137,185 teaches reacting C₁ to C₃₀ mono carboxylic acidanhydrides, and dicarboxylic anhydrides, such as acetic anhydride,succinic anhydride, etc. with an ethylene copolymer reacted with maleicanhydride and a polyalkylene polyamine to inhibit cross linking andviscosity increase due to further reaction of any primary amine groupswhich were initially unreacted.

U.S. Pat. No. 4,144,181 is similar to 4,137,185 in that it teaches usinga sulfonic acid to inactivate the remaining primary amine groups when amaleic anhydride grafted ethylene-propylene copolymer is reacted with apolyamine.

U.S. Pat. No. 4,169,063 reacts an ethylene copolymer in the absence ofoxygen and chlorine at temperatures of 150° to 250° C. with maleicanhydride followed by reaction with polyamine.

A number of prior disclosures teach avoiding the use of polyamine havingtwo primary amine groups to thereby reduce cross-linking problems whichbecome more of a problem as the number of amine moieties added to thepolymer molecule is increased in order to increase dispersancy.

German Published Application No. P3025274.5 teaches an ethylenecopolymer reacted with maleic anhydride in oil using a long chain alkylhetero or oxygen containing amine.

U.S. Pat. No. 4,132,661 grafts ethylene copolymer, using peroxide and/orair blowing, with maleic anhydride and then reacts with primary-tertiarydiamine.

U.S. Pat. No. 4,160,739 teaches an ethylene copolymer which is grafted,using a free radical technique, with alternating maleic anhydride and asecond polymerizable monomer such as methacrylic acid, which materialsare reacted with an amine having a single primary, or a singlesecondary, amine group.

U.S. Pat. No. 4,171,273 reacts an ethylene copolymer with maleicanhydride in the presence of a free radical initiator and then withmixtures of C₄ to C₁₂ n-alcohol and amine such asN-aminopropylmorpholine or dimethylamino propyl amine to form aV.I.-dispersant-pour depressant additive.

U.S. Pat. No. 4,219,432 teaches maleic anhydride grafted ethylenecopolymer reacted with a mixture of an amine having only one primarygroup together with a second amine having two or more primary groups.

German published application No. 2753569.9 shows an ethylene copolymerreacted with maleic anhydride by a free-radical technique and thenreacted with an amine having a single primary group.

German published application No. 2845288 grafts maleic anhydride on anethylene-propylene copolymer by thermal grafting at high temperaturesand then reacts with amine having one primary group.

French published application No. 2423530 grafts maleic anhydride on anethylene-propylene copolymer with maleic anhydride at 150° to 210° C.followed by reaction with an amine having one primary or secondarygroup.

The early patents such as U.S. Pat. Nos. 3,316,177 and 3,326,804 taughtthe general concept of grafting an ethylene-propylene copolymer withmaleic anhydride and then reacting with a polyalkylene polyamine such aspolyethylene amines. Subsequently, U.S. Pat. No. 4,089,794 was directedto using an oil solution for free radical peroxide grafting the ethylenecopolymer with maleic anhydride and then reaction with the polyamine.This concept had the advantage that by using oil, the entire reactioncould be carried out in an oil solution to form an oil concentrate,which is the commercial form in which such additives are sold. This wasan advantage over using a volatile solvent for the reactions, which hasto be subsequently removed and replaced by oil to form a concentrate.Subsequently, in operating at higher polyamine levels in order tofurther increase the dispersing effect, increased problems occurred withthe unreacted amine groups cross-linking and thereby causing viscosityincrease of the oil concentrate during storage and subsequent formationof haze and in some instances gelling. Even though one or more moles ofthe ethylene polyamine was used per mole of maleic anhydride duringimide formation, cross-linking became more of a problem as the nitrogencontent of the polymers was increased. One solution was to use thepolyamines and then to react the remaining primary amino groups with anacid anhydride, preferably acetic anhydride, of U.S. Pat. No. 4,137,185or the sulfonic acid of U.S. Pat. No. 4,144,181. The cross-linkingproblem could also be minimized by avoidance of the ethylene polyaminesand instead using amines having one primary group which would react withthe maleic anhydride while the other amino groups would be tertiarygroups which were substantially unreactive. Patents or publishedapplications showing the use of such primary-tertiary amines noted aboveare U.S. Pat. No. 4,219,432, wherein a part of the polyamine wasreplaced with a primary-tertiary amine; U.S. Pat. No. 4,132,661; U.S.Pat. No. 4,160,739; U.S. Pat. No. 4,171,273; German No. P2753569.9;German No. 2,845,288; and French No. 2,423,530.

U.S. Pat. No. 4,516,104 and 4,632,769 represented a further improvementover the art in that they permitted the utilization of the generallyless expensive polyamines having two primary amine groups, whileachieving good dispersancy levels, inhibiting cross-linking and allowinginitiator, e.g., peroxide, grafting in oil.

U.S. Pat. No. 4,517,104 discloses polymeric viscosity index (V.I.)improver-dispersant additives for petroleum oils particularlylubricating oils, comprising a copolymer of ethylene with one or more C₃to C₂₈ α-olefins, preferably propylene, which have been grafted withacid moieties,, e.g., maleic anhydride, preferably using a free radicalinitiator in a solvent, preferably lubricating oil, and then reactedwith a mixture of a carboxylic acid component, preferably an alkylsuccinic anhydride, and a polyamine having two or more primary aminegroups. Or the grafted polymer may be reacted with said acid componentprereacted with said polyamine to form salts, amides, imides, etc. andthen reacted with said grafted olefin polymer. These reactions canpermit the incorporation of varnish inhibition and dispersancy into theethylene copolymer while inhibiting cross-linking or gelling.

U.S. Pat. No. 4,632,769 discloses oil soluble viscosity improvingethylene copolymers such as copolymers of ethylene and propylene,reacted or grafted with ethylenically unsaturated carboxylic acidmoieties, preferably maleic anhydride moieties, and then reacted withpolyamines having two or more primary amine groups and a C₂₂ to C₂₈olefin carboxylic acid component, preferably alkylene polyamine andalkenyl succinic anhydride, respectively. These reactions can permit theincorporation of varnish inhibition and dispersancy into the ethylenecopolymer while inhibiting cross-linking or gelling.

There is, however, a need to provide multifunctional viscosity index(V.I.) improver additives which when added to oleaginous compositionssuch as lubricating oil compositions provide oil compositions whichexhibit improved or better low temperature viscometric properties.

The problem of providing V.I. improving oil additives capable ofproviding oleaginous compositions exhibiting improved low temperatureviscometric properties is addressed in U.S. Pat. No. 4,804,794 whichdiscloses segmented copolymers of ethylene and at least one otherα-olefin monomer, each copolymer being intramolecularly heterogeneousand intermolecularly homogeneous and at least one segment of thecopolymer, constituting at least 10% of the copolymer's chain, being acrystallizable segment. These copolymers are disclosed as exhibitinggood mechanical properties such as good shear stability and as beinguseful V.I. improvers which provide lubricating oils having highlydesirable viscosity and pumpability properties at low temperatures.However, these copolymers are disclosed as being V.I. improvers, andthere is no disclosure of grafting said copolymers with an ethylenicallyunsaturated grafting material or of grafting said copolymers and thenreacting the grafted copolymers with a polyamine to produce acomposition useful as a multifunctional viscosity index improver foroleaginous composition. Nor is there any disclosure in this patent ofdegrading these copolymers to reduce their molecular weight. It washeretofore generally believed that degrading these copolymers to obtaincopolymers of lower molecular weight would generally adversely affect,i.e., broaden, their narrow molecular weight distribution and affecttheir intramolecular heterogeneity and intermolecular homogeneity. This,it was believed, would have a concomitant deleterious affect upon theirability to provide oil compositions exhibiting improved low temperatureviscometric properties. It was further generally believed that theseethylene copolymers could not be grafted with conventional ethylenicallyunsaturated grafting materials or grafted with said grafting materialsand thereafter reacted with a polyamine to form a multifunctionalviscosity index improver without deleteriously or adversely affecting,i.e., broadening, their narrow molecular weight distribution (MWD) andaffecting their intermolecular homogeneity and intramolecularhomogeneity, thereby deleteriously and adversely affecting theirproperty of providing oil compositions exhibiting improved lowtemperature viscometric properties. Indeed, degrading these copolymersto reduce their molecular weights broadens their narrow molecular weightdistribution and affects their intramolecular heterogeneity andintermolecular homogeneity. However, it has surprisingly andunexpectedly been discovered that these degraded copolymers grafted witha grafting material such as carboxylic acid or anhydride and thereafterreacted with polyamines containing one primary amine group and at leastone tertiary amine group when added to oleaginous compositions provideoleaginous compositions exhibiting better low temperature viscometricproperties than oleaginous compositions containing conventionalnon-narrow MWD ethylene-α-olefin copolymers, either degraded orundegraded, grafted with grafting materials such as carboxylic acid oranhydride and thereafter reacted with polyamine containing one primaryamine group and at least one tertiary amine group.

SUMMARY OF THE INVENTION

The present invention is directed to oil soluble nitrogen containinggrafted degraded ethylene copolymers useful as multifunctional viscosityindex improvers or modifiers, e.g., as V.I. improver-dispersantadditives, in oleaginous compositions. The nitrogen containing grafteddegraded ethylene copolymers of the instant invention provide oleaginouscompositions, in particular lubricating oil compositions, exhibitingimproved viscometric properties, particularly highly desirable viscosityproperties at low temperatures, and dispersancy characteristics.

The degraded in molecular weight ethylene copolymers of the instantinvention are grafted with an ethylenically unsaturated, preferablymonounsaturated carboxylic acid grafting material and the grafteddegraded ethylene copolymers are then reacted with at least onepolyamine containing one primary amine group and one or more tertiaryamine groups.

The undegraded ethylene copolymers which are, in accordance with thepresent invention, degraded and grafted and thereafter reacted with thepolyamine containing one primary amine group and one or more tertiaryamine groups are disclosed in U.S. Pat. No. 4,804,794, which isincorporated herein by reference. These undegraded copolymers aresegmented copolymers of ethylene and at least one other alpha-olefinmonomer; each copolymer is intramolecularly heterogeneous andintermolecularly homogeneous and at least one segment of the copolymer,constituting at least 10% of the copolymer's chain, is a crystallizablesegment. For the purposes of this application, the term "crystallizablesegment" is defined to be each segment of the copolymer chain having anumber-average molecular weight of at least 700 wherein the ethylenecontent is at least 57 wt. %. The remaining segments of the copolymerchain are herein termed the "low crystallinity segments" and arecharacterized by an average ethylene content of not greater than about53 wt %. Furthermore, the molecular weight distribution (MWD) ofcopolymer is very narrow. It is well known that the breadth of themolecular weight distribution can be characterized by the ratios ofvarious molecular weight averages. For example, an indication of anarrow MWD in accordance with the present invention is that the ratio ofweight to number-average molecular weight (M_(w) /M_(n)) is less than 2.Alternatively, a ratio of the z-average molecular weight to theweight-average molecular weight (M_(z) /M_(w)) of less than 1.8 typifiesa narrow MWD in accordance with the present invention. It is known thata portion of the property advantages of copolymers in accordance withthe present invention are related to these ratios. Small weightfractions of material can disproportionately influence these ratioswhile not significantly altering the property advantages which depend onthem. For instance, the presence of a small weight fraction (e.g. 2%) oflow molecular weight copolymer can depress M_(n), and thereby raiseM_(w) /M_(n) above 2 while maintaining M_(z) /M_(w) less than 1.8.Therefore, the copolymer reactants, which are to be degraded inaccordance with the present invention, are characterized by having atleast one of M_(w) /M_(n) less than 2 and M_(z) /M_(w) less than 1.8.The copolymer reactant comprises chains within which the ratio of themonomers varies along the chain length. To obtain the intramolecularcompositional heterogeneity and narrow MWD, the ethylene copolymerreactants are preferably made in a tubular reactor.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the instant invention there are provided nitrogencontaining polymeric materials useful as multifunctional viscosity indeximprovers, particularly viscosity index improver-dispersant additives,for oleaginous materials, particularly lubricating oils, which arecomprised of certain specific types of degraded ethylene andalpha-olefin copolymers grafted with ethylenically unsaturated,preferably monounsaturated, carboxylic acid material to form grafteddegraded ethylene copolymers, and said grafted degraded ethylenecopolymers are reacted with polyamine containing one primary amine groupand at least one (i.e., one or more) tertiary amine groups.

More particularly these polymeric materials are comprised of thereaction products of:

(i) molecular weight degraded copolymer obtained by degrading undegradedcopolymer of ethylene and at least one other alpha-olefin monomer, saidundegraded copolymer comprising intramolecularly heterogeneous andintermolecularly homogeneous copolymer chains containing at least onecrystallizable segment of methylene units and at least one lowcrystallinity ethylene-alpha-olefin copolymer segment, wherein said atleast one crystallizable segment comprises at least about 10 weightpercent of said copolymer chain and contains at least about 57 weightpercent ethylene, wherein said low crystallinity segment contains notgreater than about 53 weight percent ethylene, and wherein saidcopolymer has a molecular weight distribution characterized by at leastone of a ratio of M_(w) /M_(n) of less than 2 and a ratio of M_(z)/M_(w) of less than 1.8, and wherein at least two portions of anindividual intramolecularly heterogeneous chain, each portion comprisingat least 5 weight percent of said chain, differ in composition from oneanother by at least 7 weight percent ethylene; said degraded copolymergrafted with ethylenically monounsaturated carboxylic acid material; and

(ii) polyamine containing a single primary amine group and at least onetertiary amine group.

When the nitrogen containing grafted degraded ethylene copolymers of theinstant invention are incorporated into oleaginous materials such aslubricating oils the resultant oleaginous compositions exhibit betterlow temperature viscometric properties than oleaginous compositionscontaining conventional nitrogen containing grafted ethylene copolymers.Furthermore, the nitrogen containing grafted degraded ethylenecopolymers of this invention function as dispersants in oleaginouscompositions and generally exhibit substantially similar or betterdispersancy efficacy as conventional nitrogen containing graftedethylene copolymers falling outside the scope of the instant invention.

ETHYLENE AND ALPHA-OLEFIN COPOLYMER

The undegraded ethylene and alpha-olefin copolymers which are degradedto form the degraded ethylene-α-olefin copolymers which are grafted andthen reacted with the polyamine containing one primary amine group andone or more tertiary amine groups to form the compositions of matter ofthe instant invention are copolymers of ethylene with at least one otheralpha-olefin comprised of segmented copolymer chains with compositionswhich are intramolecularly heterogeneous and intermolecularlyhomogeneous. These undegraded copolymers are described in U.S. Pat. No.4,804,794, incorporated by reference.

For convenience, certain terms that are repeated throughout the presentspecification are defined below:

a. Inter-CD defines the compositional variation, in terms of ethylenecontent, among polymer chains. It is expressed as the minimum deviation(analogous to a standard deviation) in terms of weight percent ethylene,from the average ethylene composition for a given copolymer sampleneeded to include a given weight percent of the total copolymer sample,which is obtained by excluding equal weight fractions from both ends ofthe distribution. The deviation need not be symmetrical. When expressedas a single number, for example 15% Inter-CD, it shall mean the largerof the positive or negative deviations. For example, for a Gaussiancompositional distribution, 95.5% of the polymer is within 20 wt. %ethylene of the mean if the standard deviation is 10%. The Inter-CD for95.5 wt. % of the polymer is 20 wt. % ethylene for such a sample.

b. Intra-CD is the compositional variation, in terms of ethylene, withina copolymer chain. It is expressed as the minimum difference in weight(wt. %) ethylene that exists between two portions of a single copolymerchain, each portion comprising at least 5 weight % of the chain.

c. Molecular weight distribution (MWD) is a measure of the range ofmolecular weights within a given copolymer sample. It is characterizedin terms of at least one of the ratios of weight-average tonumber-average molecular weight, M_(w) /M_(n), and z-average toweight-average molecular weight, M_(z) /M_(w), where: ##EQU1## whereinN_(i) is the number of molecules of molecular weight M_(i).

d. Viscosity Index (V.I.) is the ability of a lubricating oil toaccommodate increases in temperature with a minimum decrease inviscosity. The greater this ability, the higher the V.I. Viscosity Indexis determined according to ASTM D2270.

The instant copolymers are segmented copolymers of ethylene and at leastone other alpha-olefin monomer wherein the copolymer's chain contains atleast one crystallizable segment of ethylene monomer units, as will bemore completely described below, and at least one low crystallinityethylene-alpha-olefin copolymer segment, where in the low crystallinitycopolymer segment is characterized in the unoriented bulk state after atleast 24 hours annealing by a degree of crystallinity of less than about0.2% at 23° C., and wherein the copolymer's chain is intramolecularlyheterogeneous and intermolecularly homogeneous, and has an MWDcharacterized by at least one of M_(w) /M_(n) of less than 2 and M_(z)/M_(w) of less than 1.8. The crystallizable segments comprise from about10 to 90 wt. %, preferably from about 20 to 85 wt. %, of the totalcopolymer chain, and contain an average ethylene content which is atleast about 57 wt. %, preferably at least about 62 wt. %, and morepreferably at least about 63 wt. % and which is not greater than 95 wt.%, more preferably <85%, and most preferably <75 wt. % (e.g., from about58 to 68 wt. %). The low crystallinity copolymer segments comprise fromabout 90 to 10 wt. %, preferably from about 80 to 15 wt. %, and morepreferably from about 65 to 3.5 wt. %, of the total copolymer chain, andcontain an average ethylene content of from about 20 to 53 wt. %,preferably from about 30 to 50 wt. %, and more preferably from about 35to 50 wt. %. The copolymers comprise intramolecularly heterogeneouschain segments wherein at least two portions of an individualintramolecularly heterogeneous chain, each portion comprising at least 5weight percent of the chain and having a molecular weight of at least7000 contain at least 5 wt. % ethylene and differ in composition fromone another by at least 5 weight percent ethylene, wherein theintermolecular compositional dispersity of the polymer is such that 95wt. % of the polymer chains have a composition 15% or less different inethylene from the average weight percent ethylene composition, andwherein the copolymer is characterized by at least one or a ratio of M_(w) /M_(n) of less than 2 and a ratio of M_(z) /M_(w) of less than 1.8.

As described above, the copolymers will contain at least onecrystallizable segment rich in methylene units (hereinafter called an"M" segment) and at least one low crystallinity ethylene-alpha-olefincopolymer segment (hereinafter called a "T" segment). The copolymers maybe therefore illustrated by copolymers selected from the groupconsisting of copolymer chain structures having the following segmentsequences:

    M--T,                                                      (I)

    T.sup.1 --(M--T.sup.2)x, and                               (II)

    T.sup.1 --(M.sup.1--T.sup.2 )y--M.sup.2                    (III)

wherein M and T are defined above, M¹ and M² can be the same ordifferent and are each M segments, T¹ and T² can be the same ordifferent and are each T segments, x is an integer of from 1 to 3 and yis an integer of 1 to 3.

In structure II (x=l), the copolymer's M segment is positioned betweentwo T segments, and the M segment can be positioned substantially in thecenter of the polymer chain (that is, the T¹ and T² segments can besubstantially the same molecular weight and the sum of the molecularweight of the T¹ and T² segments can be substantially equal to themolecular weight of the M segment), although this is not essential tothe practice of this invention. Preferably, the copolymer will containonly one M segment per chain. Therefore, structures I and II (x=l) arepreferred.

Preferably, the M segments and T segments of the copolymer are locatedalong the copolymer chain so that only a limited number of the copolymerchains can associate before the steric problems associated with packingthe low crystallinity T segments prevents further agglomeration.Therefore, in a preferred embodiment, the M segment is located near thecenter of the copolymer chain and only one M segment is in the chain.

As will be shown below, a copolymer of the structure

    M.sup.1 --(T--M.sup.2).sub.z                               (IV)

(wherein M¹, M² and T are as defined above, and wherein z is an integerof at least 1) are undesirable as viscosity modifier polymers. It hasbeen found that solutions of structure IV copolymers in oil tend to geleven when the M and T portions have exactly the same composition andmolecular weight as structure II copolymers (with x=z=l). It is believedthis poor viscosity modifier performance is due to the inability of acenter T segment to sterically stabilize against association.

The M segments of the copolymers of this invention comprise ethylene andcan also comprise at least one other alpha-olefin, e.g., containing 3 to18 carbon atoms. The T segments comprise ethylene and at least one otheralpha-olefin, e.g., alpha-olefins containing 3 to 18 carbon atoms. The Mand T segments can also comprise other polymerizable monomers, e.g.,non-conjugated dienes or cyclic mono-olefins.

Since the present invention is considered to be most preferred in thecontext of ethylene-propylene (EPM) copolymers it will be described indetail in the context of EPM.

Copolymer (i)(a) in accordance with the present invention is preferablymade in a tubular reactor. When produced in a tubular reactor withmonomer feed only at the tube inlet, it is known at the beginning of thetubular reactor, ethylene, due to its high reactivity , will bepreferentially polymerized. The concentration of monomers in solutionchanges along the tube in favor of propylene as the ethylene isdepleted. The result, with monomer feed only at the inlet, is copolymerchains which are higher in ethylene concentration in the chain segmentsgrown near the reactor inlet (as defined at the point at which thepolymerization reaction commences), and higher in propyleneconcentration in the chain segments formed near the reactor outlet.These copolymer chains are therefore tapered in composition. Anillustrative copolymer chain of ethylene-propylene is schematicallypresented below with E representing ethylene constituents and Prepresenting propylene constituents in the chain: ##STR1##

As can be seen from this illustrative schematic chain, the far left-handsegment (1) thereof represents that portion of the chain formed at thereactor inlet where the reaction mixture is proportionately richer inthe more reactive constituent ethylene. This segment comprises fourethylene molecules and one propylene molecule. However, as subsequentsegments are formed from left to right with the more reactive ethylenebeing depleted and the reaction mixture proportionately increasing inpropylene concentration, the subsequent chain segments become moreconcentrated in propylene. The resulting chain is intramolecularlyheterogeneous.

The property, of the copolymer discussed herein, related tointramolecular compositional dispersity (compositional variation withina chain) shall be referred to as Intra-CD, and that related tointermolecular compositional dispersity (compositional variation betweenchains) shall be referred to as Inter-CD.

For copolymers in accordance with the present invention, composition canvary between chains as well as along the length of the chain. An objectof this invention is to minimize the amount of inter-chain variation.The Inter-CD can be characterized by the difference in compositionbetween the copolymer fractions containing the highest and lowestquantity of ethylene. Techniques for measuring the breadth of thiInter-CD are known as illustrated in "Polymerization of ethylene andpropylene to amorphous copolymers with catalysts of vanadium oxychlorideand alkyl aluminum halides"; E. Junghanns, A. Gumboldt and G. Bier;Makromol. Chem., V. 58 (12/12/62): 18-42, wherein ap-xylene/dimethylformamide solvent/nonsolvent was used to fractionatecopolymer into fractions of differing intermolecular composition. Othersolvent/nonsolvent systems can be used as hexane/2 propanol, as will bediscussed in more detail below.

The Inter-CD of copolymer in accordance with the present invention issuch that 95 wt. % of the copolymer chains have an ethylene compositionthat differs from the average weight percent ethylene composition by 15wt. % or less. The preferred Inter-CD is about 134 or less, with themost preferred being about 10% or less. In comparison, Junghanns et al.found that their tubular reactor copolymer had an Inter-CD of greaterthan 15 wt. %.

Broadly, the Intra-CD of copolymer in accordance with the presentinvention is such that at least two portions of an individualintramolecularly heterogeneous chain, each portion comprising at least 5weight percent of the chain, differ in composition from one another byat least 7 weight percent ethylene. Unless otherwise indicated, thisproperty of Intra-CD as referred to herein is based upon at least two 5weight percent portions of copolymer chain. The Intra-CD of copolymer inaccordance with the present invention can be such that at least twoportions of copolymer chain differ by at least 10 weight percentethylene. Differences of at least 20 weight percent, as well as, of atleast 40 weight percent ethylene are also considered to be in accordancewith the present invention.

The experimental procedure for determining Intra-CD is as follows. Firstthe Inter-CD is established as described below, then the polymer chainis broken into fragments along its contour and the Inter-CD of thefragments is determined. The difference in the two results is due toIntra-CD as can be seen in the illustrative example below.

Consider a heterogeneous sample polymer containing 30 monomer units. Itconsists of 3 molecules designated A, B, C.

    ______________________________________                                        A       EEEEPEEEPEEEPPEEPPEPPPEPPPPPPP                                        B       EEEEEPEEEPEEEPPEEEPPPEPPPEEPPP                                        C       EEPEEEPEEEPEEEPEEEPPEEPPPEEPPP                                        ______________________________________                                    

Molecule A is 36.8 wt. % ethylene, B is 46.6%, and C is 50% ethylene.The average ethylene content for the mixture is 44.3%. For this samplethe Inter-CD is such that the highest ethylene polymer contains 5.7%more ethylene than the average while the lowest ethylene content polymercontains 7.5% less ethylene than the average. Or, in other words, 100weight % of the polymer is within +5.7% and -7.5% ethylene about anaverage of 44.3%. Accordingly, the Inter-CD is 7.5% when the givenweight % of the polymer is 100%.

If the chains are broken into fragments, there will be a new Inter-CD.For simplicity, consider first breaking only molecule A into fragmentsshown by the slashes as follows:

    EEEP/EEEPE/EEPPE/EPPEP/PPEPP/PPPPP

Portions of 72.7%, 72.7%, 50%, 30.8%, 14.3% and 0% ethylene areobtained. If molecules B and C are similarly broken and the weightfractions of similar composition are grouped a new Inter-CD is obtained.

In order to determine the fraction of a polymer which isintramolecularly heterogeneous in a mixture of polymers combined fromseveral sources the mixture must be separated into fractions which showno further heterogenity upon subsequent fractionation. These fractionsare subsequently fractured and fractionated to reveal which areheterogeneous.

The fragments into which the original polymer is broken should be largeenough to avoid end effects and to give a reasonable opportunity for thenormal statistical distribution of segments to form over a given monomerconversion range in the polymerization. Intervals of ca 5 weight % ofthe polymer are convenient. For example, at an average polymer molecularweight of about 105, fragments of ca 5000 molecular weight areappropriate. A detailed mathematical analysis of plug flow or batchpolymerization indicates that the rate of change of composition alongthe polymer chain contour will be most severe at high ethyleneconversion near the end of the polymerization. The shortest fragmentsare needed here to show the low ethylene content sections.

The best available technique for determination of compositionaldispersity for non-polar polymers is solvent/nonsolvent fractionationwhich is based on the thermodynamics of phase separation. This techniqueis described in "Polymer Fractionation", M. Cantow editor, Academic1967, p. 341 and in H. Inagaki, T. Tanaku, "Developments in PolymerCharacterization", 3, 1, (1982). These are incorporated herein byreference.

For non-crystalline copolymers of ethylene and propylene, molecularweight governs insolubility more than does composition in asolvent/nonsolvent solution. High molecular weight polymer is lesssoluble in a given solvent mix. Also, there is a systematic correlationof molecular weight with ethylene content for the polymers describedherein. Since ethylene polymerizes much more rapidly than propylene,high ethylene polymer also tends to be high in molecular weight.Additionally, chains rich in ethylene tend to be less soluble inhydrocarbon/polar non-solvent mixtures than propylene-rich chains.Furthermore, for crystalline segments, solubility is significantlyreduced. Thus, the high molecular weight, high ethylene chains areeasily separated on the basis of thermodynamics.

A fractionation procedure is as follows: Unfragmented polymer isdissolved in n-hexane at 23° C. to form ca a 1% solution (1 g.polymer/100 cc hexane). Isopropyl alcohol is titrated into the solutionuntil turbidity appears at which time the precipitate is allowed tosettle. The supernatant liquid is removed and the precipitate is driedby pressing between Mylar polyethylene terphthalate) film at 150° C.Ethylene content is determined by ASTM method D-3900. Titration isresumed and subsequent fractions are recovered and analyzed until 100%of the polymer is collected. The titrations are ideally controlled toproduce fractions of 5-10% by weight of the original polymer, especiallyat the extremes of composition.

To demonstrate the breadth of the distribution, the data are plotted as% ethylene versus the cumulative weight of polymer as defined by the sumof half the weight % of the fraction of that composition plus the totalweight % of the previously collected fractions.

Another portion of the original polymer is broken into fragments. Asuitable method for doing this is by thermal degradation according tothe following procedure: In a sealed container in a nitrogen-purgedoven, a 2 mm thick layer of the polymer is heated for 60 minutes at 330°C. (The time or temperature can be empirically adjusted based on theethylene content and molecular weight of the polymer.) This should beadequate to reduce a 105 molecular weight polymer to fragments of ca5000 molecular weight. Such degradation does not substantially changethe average ethylene content of the polymer, although propylene tends tobe lost on scission in preference to ethylene. This polymer isfractionated by the same procedure as the high molecular weightprecursor. Ethylene content is measured as well as molecular weight onselected fractions.

The procedure to characterize intramolecular heterogeneity is laboriousand even when performed at an absolute optimum, does not show how thesegments of the chain are connected. In fact it is not possible, withcurrent technology, to determine the polymer structure without recourseto the synthesis conditions. With knowledge of the synthesis conditions,the structure can be defined as follows.

Ethylene, propylene or high alpha-olefin polymerizations with transitionmetal catalysts can be described by the terminal copolymerization model,to an approximation adequate for the present purpose. (G. Ver Strate,Encyclopedia of Polymer Science and Engineering, vol. 6, 522 (1986)). Inthis model, the relative reactivity of the two monomers is specified bytwo reactivity ratios defined as follows: ##EQU2## Given these twoconstants, at a given temperature, the ratio of the molar amount ofethylene, E, to the molar amount of propylene, P, entering the chainfrom a solution containing ethylene and propylene at molarconcentrations [E] and [P] respectively is ##EQU3##

The relation of E and P to the weight % ethylene in the polymer is asfollows ##EQU4##

The values of R₁ and R₂ are dependent on the particular comonomer andcatalyst employed to prepare the polymer, the polymerization temperatureand, to some extent, the solvent.

For all transition metal catalysts specified herein, R₁ is significantlylarger than R₂. Thus, as can be seen from equation (1), ethylene will beconsumed more rapidly than propylene for a given fraction of the monomerin the reacting medium. Thus, the ratio of [E]/[P] will decrease as themonomers are consumed. Only if R₁ =R₂ will the composition in thepolymer equal that in the reacting medium.

If the amount of monomer that has reacted at a given time in a batchreactor or at a given point in a tubular reactor can be determined, itis possible through equation (1), to determine the instantaneouscomposition being formed at a given point along the polymer chain.Demonstration of narrow MWD and increasing MW along the tube proves thecompositional distribution is intramolecular. The amount of polymerformed can be determined in either of two ways. Samples of thepolymerizing solution may be collected, with appropriate quenching toterminate the reaction at various points along the reactor, and theamount of polymer formed evaluated. Alternatively, if the polymerizationis run adiabatically and the heat of polymerization is known, the amountof monomer converted may be calculated from the reactor temperatureprofile.

Finally, if the average composition of the polymer is measured at aseries of locations along the tube, or at various times in the batchpolymerization case, it is possible to calculate the instantaneouscomposition of the polymer being made. This technique does not requireknowledge of R₁ and R₂ or the heat of polymerization, but it doesrequire access to the polymer synthesis step.

All of these methods have been employed with consistent results.

For the purpose of this patent, R₁ and R₂ thus simply serve tocharacterize the polymer composition in terms of the polymerizationconditions. By defining R₁ and R₂, we are able to specify theintramolecular compositional distribution. In the examples shown belowwhere VCl₄ and ethylaluminum sesquichloride are employed in hexane assolvent, R₁ =1.8 exp(+500/RT_(k)) and R₂ =3.2 exp(-1500/RT_(k)). Where"R" is the gas constant (1.98 col/deg-mole) and "T_(k) " is degreesKelvin. For reference, at 20° C. R₁ =9.7, R₂ =0.02.

The R₁ and R₂ given above predict the correct final average polymercomposition. If the R₁ and R₂ and expression (2) are someday proven tobe inaccurate the polymer intramolecular compositional distribution willremain as defined herein in terms of the polymerization conditions butmay have to be modified on the absolute composition scales. There islittle likelihood that they are in error by more than a few percent,however.

Ethylene content is measured by ASTM-D3900 for ethylene-propylenecopolymers between 35 and 85 wt. % ethylene. Above 85% ASTM-D2238 can beused to obtain methyl group concentrations which are related to percentethylene in an unambiguous manner for ethylene-propylene copolymers.When comonomers other than propylene are employed no ASTM tests coveringa wide range of ethylene contents are. available; however, proton andcarbon-13 nuclear magnetic reasonance spectroscopy can be employed todeterktine the composition of such polymers. These are absolutetechniques requiring no calibration when operated such that all nucleiiof a given element contribute equally to the spectra. For ranges notcovered by the ASTM tests for ethylene-propylene copolymers, thesenuclear magnetic resonance methods can also be used.

Molecular weight and molecular weight distribution are measured using aWaters 150C gel permeation chromatography equipped with a ChromatixKKX-6 (LDC-Milton Roy, Riviera Beach, Fla.) on-line light scatteringphotometer. The system is used at 135° C. with 1,2,4 trichlorobenzene asmobile phase. Showdex (Showa-Denko America, Inc.) polystyrene gelcolumns 802, 803, 804 and 805 are used. This technique is discussed in"Liquid Chromatography of Polymers and Related Materials III", J. Cazeseditor. Marcel Dekker, 1981, p. 207 (incorporated herein by reference).No corrections for column spreading are employed; however, data ongenerally accepted standards, e.g., National Bureau of StandardsPolyethene 1484 and anionically produced hydrogenated polyisoprenes (analternating ethylene-propylene copolymer) demonstrate that suchcorrections on M_(w) /M_(n) or M_(z) /M_(w) are less than .05 unit.M_(w) /M_(n) is calculated from an elution time-molecular weightrelationship whereas M_(z) /M_(w) is evaluated using the lightscattering photometer. The numerical analyses can be performed using thecommercially available computer software GPC2, MOLWT2 available fromLDC/Milton Roy-Riviera Beach, Fla.

As already noted, copolymers in accordance with the present inventionare comprised of ethylene and at least one other alpha-olefin. It isbelieved that such alpha-olefins could include those containing 3 to 18carbon atoms, e.g., propylene, butene-1, pentene-1, etc. Alpha-olefinsof 3 to 6 carbons are preferred due to economic considerations. The mostpreferred copolymers in accordance with the present invention are thosecomprised of ethylene and propylene.

As is well known to those skilled in the art, copolymers of ethylene andhigher alpha-olefins such as propylene often include other polymerizablemonomers. Typical of these other monomers may be non-conjugated dienessuch as the following non-limiting examples:

a. straight chain acyclic dienes such as: 1,4-hexadiene; 1,6-octadiene;

b. branched chain acyclic dienes such as: 5-methyl-1, 4-hexadiene; 3,7-dimethyl-1,6-octadiene; 3, 7-dimethyl-1,7-octadiene and the mixedisomers of dihydro-myrcene and dihydroocinene;

c. single ring alicyclic dienes such as: 1, 4-cyclohexadiene;1,5-cyclooctadiene; and 1,5-cyclododecadiene;

d. multi-ring alicyclic fused and bridged ring dienes such as:tetrahydroindene; methyltetrahydroindene; dicyclopentadiene;bicyclo-(2,2,1)-hepta-2, 5-diene; alkenyl, alkylidene, cycloalkenyl andcycloalkylidene norbornenes such as 5-methylene-2-norbornene (MNB),5-ethylidene-2-norbornene (ENB), 5-propylene-2-norbornene,5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene;5-cyclohexylidene-2-norbornene.

Of the non-conjugated dienes typically used to prepare these copolymers,dienes containing at least one of the double bonds in a strained ringare preferred. The most preferred diene is 5-ethylidene-2-norbornene(ENB). The amount of diene (wt. basis) in the copolymer could be fromabout 0% to 20% with 0% to 15% being preferred. The most preferred rangeis 0% to 10%.

As already noted, the most preferred copolymer in accordance with thepresent invention is ethylene-propylene. The average ethylene content ofthe copolymer could be as low as about 20% on a weight basis. Thepreferred minimum is about 25%. A more preferred minimum is about 30%.The maximum ethylene content could be about 90% on a weight basis. Thepreferred maximum is about 85%, with the most preferred being about 80%.Preferably, the copolymers of this invention intended for use asviscosity modifier-dispersant contain from about 35 to 75 wt. %ethylene, and more preferably from about 50 to 70 wt. % ethylene.

The molecular weight of copolymer made in accordance with the presentinvention can vary over a wide range. It is believed that theweight-average molecular weight could be as low as about 2,000. Thepreferred minimum is about 10,000. The most preferred minimum is about20,000. it is believed that the maximum weight-average molecular weightcould be as high as about 12,000,000. The preferred maximum is about1,000,000. The most preferred maximum is about 750,000. An especiallypreferred range of weight-average molecular weight for copolymers to bedegraded in accordance with the instant invention for use in thepreparation of the multifunctional viscosity index modifiers of thisinvention.

The copolymers of this invention will also be generally characterized bya Mooney viscosity (i.e., ML(1,+4,) 125° C.) of from about 1 to 100,preferably from about 5 to 70, and more preferably from about 8 to 65,and by a thickening efficiency ("T.E.") of from about 0.4 to 5.0,preferably from about 1.0 to 4.2, most preferably from about 1.4 to 3.9.

Another feature of copolymer of the present invention is that themolecular weight distribution (MWD) is very narrow, as characterized byat least one of a ratio of M_(w) /M_(n) of less than 2 and a ratio ofM_(z) /M_(w) of less than 1.8. As relates to EPM and EPDM, a typicaladvantage of such copolymers having narrow MWD is resistance to sheardegradation. Particularly for oil additive applications, the preferredcopolymers have M_(w) /M_(n) less than about 1.5, with less than about1.25 being most preferred. The preferred M_(z) /M_(w) is less than about1.5, with less than about 1.2 being most preferred.

The copolymers of the instant invention may be produced bypolymerization of a reaction mixture comprised of catalyst, ethylene andat least one additional alpha-olefin monomer, wherein the amounts ofmonomer, and preferably ethylene, is varied during the course of thepolymerization in a controlled manner as will be hereinafter described.Solution polymerizations are preferred.

Any known solvent for the reaction mixture that is effective for thepurpose can be used in conducting solution polymerizations in accordancewith the present invention. For example, suitable solvents would behydrocarbon solvents such as aliphatic, cycloaliphatic and aromatichydrocarbon solvents, or halogenated versions of such solvents. Thepreferred solvents are C₁₂ or lower, straight chain or branched chain,saturated hydrocarbons, C₅ to C₉ saturated alicyclic or aromatichydrocarbons or C₂ to C₆ halogenated hydrocarbons. Most preferred areC₁₂ or lower, straight chain or branched chain hydrocarbons particularlyhexane. Non-limiting illustrative examples of solvents are butane,pentane, hexane, heptane, cyclopentane, cyclohexane, cycloheptane,methyl cyclopentane, methyl cyclohexane, isooctane, benzene, toluene,xylene, chloroform, chlorobenzenes, tetrachloroethylene, dichloroethaneand trichloroethane.

These polymerizations are carried out in a mix-free reactor system,which is one in which substantially no mixing occurs between portions ofthe reaction mixture that contain polymer chains initiated at differenttimes. Suitable reactors are a continuous flow tubular or a stirredbatch reactor. A tubular reactor is well known and is designed tominimize mixing of the reactants in the direction of flow. As a result,reactant concentration will vary along the reactor length. In contrast,the reaction mixture in a continuous flow stirred tank reactor (CFSTR)is blended with the incoming feed to produce a solution of essentiallyuniform composition everywhere in the reactor. Consequently, the growingchains in a portion of the reaction mixture will have a variety of agesand thus a single CFSTR is not suitable for the process of thisinvention. However, it is well known that 3 or more stirred tanks inseries with all of the catalyst fed to the first reactor can approximatethe performance of a tubular reactor. Accordingly, such tanks in seriesare considered to be in accordance with the present invention.

A batch reactor is a suitable vessel, preferably equipped with adequateagitation, to which the catalyst, solvent, and monomer are added at thestart of the polymerization. The charge of reactants is then left topolymerize for a time long enough to produce the desired product orchain segment. For economic reasons, a tubular reactor is preferred to abatch reactor for carrying out the processes of this invention.

In addition to the importance of the reactor system to make copolymersin accordance with the present invention, the polymerization should beconducted such that:

(a) the catalyst system produces essentially one active catalystspecies,

(b) the reaction mixture is essentially free of chain transfer agents,and

(c) the polymer chains are essentially all initiated simultaneously,which is at the same time for a batch reactor or at the same point alongthe length of the tube for a tubular reactor.

To prepare copolymer structures II and III above (and, optionally, toprepare copolymer structure I above), additional solvent and reactants(e.g., at least one of the ethylene, alpha-olefin and diene) will beadded either along the length of a tubular reactor or during the courseof polymerization in a batch reactor, or to selected stages of stirredreactors in series in a controlled manner (as will be hereinafterdescribed) to form the copolymers of this invention. However, it isnecessary to add essentially all of the catalyst at the inlet of thetube or at the onset of batch reactor operation to meet the requirementthat essentially all polymer chains are initiated simultaneously.

Accordingly, polymerization in accordance with the present invention arecarried out:

(a) in at least one mix-free reactor,

(b) using a catalyst system that produces essentially one activecatalyst species,

(c) using at least one reaction mixture which is essentially transferagent-free, and

(d) in such a manner and under conditions sufficient to initiatepropagation of essentially all polymer chains simultaneously.

Since the tubular reactor is the preferred reactor system for carryingout polymerizations in accordance with the present invention, thefollowing illustrative descriptions are drawn to that system, but willapply to other reactor systems as will readily occur to the artisanhaving the benefit of the present disclosure.

In practicing polymerization processes in accordance with the presentinvention, use is preferably made of at least one tubular reactor. Thus,in its simplest form, such a process would make use of but a single,reactor. However, as would readily occur to the artisan having thebenefit of the present disclosure, a series of reactors could be usedwith multiple monomer feed to vary intramolecular composition asdescribed below.

The composition of the catalyst used to produce alpha-olefin copolymershas a profound effect on copolymer product properties such ascompositional dispersity and MWD. The catalyst utilized in practicingprocesses in accordance with the present invention should be such as toyield essentially one active catalyst species in the reaction mixture.More specifically, it should yield one primary active catalyst specieswhich provides for substantially all of the polymerization reaction.Additional active catalyst species could provide as much as 35% (weight)of the total copolymer. Preferably, they should account for about 10% orless of the copolymer. Thus, the essentially one active species shouldprovide for at least 65% of the total copolymer produced, preferably forat least 90% thereof. The extent to which a catalyst species contributesto the polymerization can be readily determined using thebelow-described techniques for characterizing catalyst according to thenumber of active catalyst species.

Techniques for characterizing catalyst according to the number of activecatalyst species are within the skill of the art, as evidenced by anarticle entitled "Ethylene-Propylene Copolymers. Reactivity Ratios,Evaluation and Significance", C. Cozewith and G. Ver Strate,Macromolecules, 4, 482 (1971), which is incorporated herein byreference.

It is disclosed by the authors that copolymers made in a continuous flowstirred reactor should have an MWD characterized by M_(w) /M_(n) =2 anda narrow Inter-CD when one active catalyst species is present. By acombination of fractionation and gel permeation chromatography (GPC) itis shown that for single active species catalysts the compositions ofthe fractions vary no more than ±3% about the average and the MWD(weight- to number-average ratio) for these samples approaches 2. It isthis latter characteristic (M_(w) /M_(n) of about 2) that is deemed themore important in identifying a single active catalyst species. On theother hand, other catalysts gave copolymer with an Inter-CD greater than±10% about the average and multi-modal NWD often with M_(w) /M_(n)greater than 10. These other catalysts are deemed to have more than oneactive species.

Catalyst systems to be used in carrying out processes in accordance withthe present invention may be Ziegler catalysts, which may typicallyinclude:

(a) a compound of a transition metal, i.e., a metal of Groups I-B,III-B, IVB, VB, VIB, VIIB and VIII of the Periodic Table, and (b) anorganometal compound of a metal of Groups I-A, II-A, II-B and III-A ofthe Periodic Table.

The preferred catalyst system in practicing processes in accordance withthe present invention comprises hydrocarbon-soluble vanadium compound inwhich the vanadium valence is 3 to 5 and an organo-aluminum compound,with the proviso that the catalyst yields essentially one activecatalyst species as described above. At least one of the vanadiumcompound/organoaluminum pair selected must also contain a valence-bondedhalogen.

In terms of formulas, vanadium compounds useful in practicing processesin accordance with the present invention could be:

    ______________________________________                                        O               (1)                                                           VCl.sub.x (OR).sub.3-x                                                        where x = 0 - 3 and R = a hydrocarbon radical;                                VCl.sub.4 ;                                                                   VO(AcAc).sub.2,                                                               where AcAc = acetyl acetonate which may or                                    may not be alkyl-substituted (e.g..sub.1 to C.sub.6                           alkyl);                                                                       V(AcAc).sub.3 ;                                                               V(dicarbonyl moiety)3;                                                        VOCl.sub.x (AcAc).sub.3-x,                                                    where x = 1 or 2;                                                             V(dicarbonyl moiety).sub.3 Cl; and                                            VCl.sub.3.nB,                                                                 ______________________________________                                    

where n=2-3, B=Lewis base capable of making hydrocarbon-solublecomplexes with VCl₃, such as tetrahydrofuran, 2-methyl-tetrahydrofuranand dimethyl pyridine, and the dicarbonyl moiety is derived from adicarbonyl compound of the formula: ##STR2##

In formula (1) above, each R (which can be the same or different)preferably represents a C₁ to C₁₀ aliphatic, alicyclic or aromatichydrocarbon radical such as ethyl (Et), phenyl, isopropyl, butyl,propyl, n-butyl, i-butyl, t-butyl, hexyl, cyclohexyl, octyl, naphthyl,etc. R, preferably represents an alkylene divalent radical of 1 to 6carbons (e.g. --CH₂ --, --C₂ H₄ --, etc.). Nonlimiting illustrativeexamples of formula (1) compounds are vanadyl trihalides, alkoxy halidesand alkoxides such as VOCl₃, VOCl₂ (OBu) where Bu=butyl, and VO(OC₂H₅)₃. The most preferred vanadium compounds are VCl₄, VOCl₃ and VOCl₂(OR).

As already noted, the co-catalyst is preferably organo-aluminumcompound. In terms of chemical formulas, these compounds could be asfollows: R1 ? AlR₃,Al(OR)R₂, AlR₂ Cl,R₂ Al AlR₂, AlR,RCl,AlR₂ I, Al₂ R₃Cl₃,and AlRCl₂,

where R and R, represent hydrocarbon radicals, the same or different, asdescribed above with respect to the vanadium compound formula. The mostpreferred organo-aluminum compound is an aluminum alkyl sesquichloridesuch as Al₂ Et₃ Cl₃ or Al₂ (iBu)₃ Cl₃.

In terms of performance, a catalyst system comprised of VCl₄ and Al₂ R₃Cl₃, preferably where R is ethyl, has been shown to be particularlyeffective. For best catalyst performance, the molar amounts of catalystcomponents added to the reaction mixture should provide a molar ratio ofaluminum/vanadium (Al/V) of at least about 2. The preferred minimum Al/Vis about 4. The maximum Al/V is based primarily on the considerations ofcatalyst expense and the desire to minimize the amount of chain transferthat may be caused by the organo-aluminum compound (as explained indetail below). Since, as is known certain organo-aluminum compounds actas chain transfer agents, if too much is present in the reaction mixturethe M_(w) /M_(n) of the copolymer may rise above 2. Based on theseconsiderations, the maximum Al/V could be about 25, however, a maximumof about 17 is more preferred. The most preferred maximum is about 15.

With reference again to processes for making copolymer in accordancewith the present invention, it is well known that certain combinationsof vanadium and aluminum compounds that can comprise the catalyst systemcan cause branching and gelation during the polymerization for polymerscontaining high levels of diene. To prevent this from happening Lewisbases such as ammonia, tetrahydrofuran, pyridine, tributylamine,tetrahydrothiophene, etc., can be added to the polymerization systemusing techniques well known to those skilled in the art.

Chain transfer agents for the Ziegler-catalyzed, polymerization ofalpha-olefins are well known and are illustrated, by way of example, byhydrogen or diethyl zinc for the production of EPM and EPDM. Such agentsare very commonly used to control the molecular weight of EPM and EPDMproduced in continuous flow stirred reactors. For the essentially singleactive species Ziegler catalyst systems used in accordance with thepresent invention, addition of chain transfer agents to a CFSTR reducesthe polymer molecular weight but does not affect the molecular weightdistribution. On the other hand, chain transfer reactions during tubularreactor polymerization in accordance with the present invention broadenpolymer molecular weight distribution and Inter-CD. Thus the presence ofchain transfer agents in the reaction mixture should be minimized oromitted altogether. Although difficult to generalize for all possiblereactions, the amount of chain transfer agent used should be limited tothose amounts that provide copolymer product in accordance with thedesired limits as regards MWD and compositional dispersity. It isbelieved that the maximum amount of chain transfer agent present in thereaction mixture could be as high as about 0.2 mol/mol of transitionmetal, e.g., vanadium, again provided that the resulting copolymerproduct is in accordance with the desired limits as regards MWD andcompositional dispersity. Even in the absence of added chain transferagent, chain transfer reactions can occur because propylene and theorgano-aluminum cocatalyst can also act as chain transfer agents. Ingeneral, among the organo-aluminum compounds that in combination withthe vanadium compound yield just one active species, the organo-aluminumcompound that gives the highest copolymer molecular weight at acceptablecatalyst activity should be chosen. Furthermore, if the Al/V ratio hasan effect on the molecular weight of copolymer product, that Al/V shouldbe used which gives the highest molecular weight also at acceptablecatalyst activity. Chain transfer with propylene can best be limited byavoiding excessively elevated temperature during the polymerization asdescribed below.

Molecular weight distribution and Inter-CD are also broadened bycatalyst deactivation during the course of the polymerization whichleads to termination of growing chains. It is well known that thevanadium-based Ziegler catalysts used in accordance with the presentinvention are subject to such deactivation reactions which depend to anextent upon the composition of the catalyst. Although the relationshipbetween active catalyst lifetime and catalyst system composition is notknown at present, for any given catalyst, deactivation can be reduced byusing the shortest residence time and lowest temperature in the reactorthat will produce the desired monomer conversions.

Polymerizations in accordance with the present invention should beconducted in such a manner and under conditions sufficient to initiatepropagation of essentially all copolymer chains simultaneously. This canbe accomplished by utilizing the process steps and conditions describedbelow.

The catalyst components are preferably premixed, that is, reacted toform active catalyst outside of the reactor, to ensure rapid chaininitiation. Aging of the premixed catalyst system, that is, the timespent by the catalyst components (e.g., vanadium compound andorgano-aluminum) in each other's presence outside of the reactor, shouldpreferably be kept within limits. If not aged for a sufficient period oftime, the components will not have reacted with each other sufficientlyto yield an adequate quantity of active catalyst species, with theresult of nonsimultaneous chain initiation. Also, it is known that theactivity of the catalyst species will decrease with time so that theaging must be kept below a maximum limit. It is believed that theminimum aging period, depending on such factors as concentration ofcatalyst components, temperature and mixing equipment, could be as lowas about 0.1 second. The preferred minimum aging period is about 0.5second, while the most preferred minimum aging period is about 1 second.While the maximum aging period could be higher, for the preferredvanadium/organo-aluminum catalyst system the preferred maximum is about200 seconds. A more preferred maximum is about 100 seconds. The mostpreferred maximum aging period is about 50 seconds. The premixing couldbe performed at low temperature such as 40° C. or below. It is preferredthat the premixing be performed at 25° C. or below, with 20° C. or belowbeing most preferred.

Preferably, the catalyst components are premixed in the presence of theselected polymerization diluent or solvent under rapid mixingconditions, e.g., at impingement Reynolds Numbers (NRE) of at least10,000, more preferably at least 50,000, and most preferably at least100,000. Impingement Reynolds number is defined as ##EQU5## where N isfluid flow velocity (cm./sec.), D is inside tube diameter (cm), ρ isfluid density (g./cm.³) and μ is fluid viscosity (poise).

The temperature of the reaction mixture should also be kept withincertain limits. The temperature at the reactor inlets should be highenough to provide complete, rapid chain initiation at the start of thepolymerization reaction. The length of time the reaction mixture spendsat high temperature must be short enough to minimize the amount ofundesirable chain transfer and catalyst deactivation reactions.

Temperature control of the reaction mixture is complicated somewhat bythe fact that the polymerization reaction generates large quantities ofheat. This problem is, preferably, taken care of by using prechilledfeed to the reactor to absorb the heat of polymerization. With thistechnique, the reactor is operated adiabatically and the temperature isallowed to increase during the course of polymerization. As analternative to feed prechill, heat can be removed from the reactionmixture, for example, by a heat exchanger surrounding at least a portionof the reactor or by well-known autorefrigeration techniques in the caseof batch reactors or multiple stirred reactors in series.

If adiabatic reactor operation is used, the inlet temperature of thereactor feed could be about from -50° C. to 150° C. It is believed thatthe outlet temperature of the reaction mixture could be as high as about200° C. The preferred maximum outlet temperature is about 70° C. Themost preferred maximum is about 60° C. In the absence of reactorcooling, such as by a cooling jacket, to remove the heat ofpolymerization, it has been determined (for a mid-range ethylene contentEP copolymer and a solvent with heat capacity similar to hexane) thatthe temperature of the reaction mixture will increase from reactor inletto outlet by about 13° C. per weight percent of copolymer in thereaction mixture (weight of copolymer per weight of solvent).

Having the benefit of the above disclosure, it would be well within theskill of the art to determine the operating temperature conditions formaking copolymer in accordance with the present invention. For example,assume an adiabatic reactor and an outlet temperature of 35° C. aredesired for a reaction mixture containing 5% copolymer. The reactionmixture will increase in temperature by about 13° C. for each weightpercent copolymer or 5 wt. % ×13° C./wt. % =65° C. To maintain an outlettemperature of 35° C., it will thus require a feed that has beenprechilled to 35° C.-65° C.=-30° C. In the instance that externalcooling is used to absorb the heat of polymerization, the feed inlettemperature could be higher with the other temperature constraintsdescribed above otherwise being applicable.

Because of heat removal and reactor temperature limitations, thepreferred maximum copolymer concentration at the reactor outlet is 25wt./100 wt. diluent. The most preferred maximum concentration is 15wt/100 wt. There is no lower limit to concentration due to reactoroperability, but for economic reasons it is preferred to have acopolymer concentration of at least 2 wt/100 wt. Most preferred is aconcentration of at least 3 wt/100 wt.

The rate of flow of the reaction mixture through the reactor should behigh enough to provide good mixing of the reactants in the radialdirection and minimize mixing in the axial direction. Good radial mixingis beneficial not only to both the Intra- and Inter-CD of the copolymerchains but also to minimize radial temperature gradients due to the heatgenerated by the polymerization reaction. Radial temperature gradientsin the case of multiple segment polymers will tend to broaden themolecular weight distribution of the copolymer since the polymerizationrate is faster in the high temperature regions resulting from poor heatdissipation. The artisan will recognize that achievement of theseobjectives is difficult in the case of highly viscous solutions. Thisproblem can be overcome to some extent through the use of radial mixingdevices such as static mixers (e.g., those produced by the KenicsCorporation).

It is believed that residence time of the reaction mixture in themix-free reactor can vary over a wide range. It is believed that theminimum could be as low as about 0.2 second. A preferred minimum isabout 0.5 second. The most preferred minimum is about 1 second. It isbelieved that the maximum could be as high as about 3600 seconds. Apreferred maximum is about 40 seconds. The most preferred maximum isabout 20 seconds.

Preferably, the fluid flow of the polymerization reaction mass throughthe tubular reactor will be under turbulent conditions, e.g., at a flowReynolds Number (NR) of at least 10,000, more preferably at least50,000, and most preferably at least 100,000 (e.g., 150,000 to 250,000),to provide the desired radial mixing of the fluid in the reactor. FlowReynolds Number is defined as ##EQU6## wherein N' is fluid flow velocity(cm./sec.), D' is inside tube diameter of the reactor (cm.), ρ is fluiddensity (g./cm.³) and μ is fluid viscosity (poise).

If desired, catalyst activators for the selected vanadium catalysts canbe used as long as they do not cause the criteria for a mix-free reactorto be violated, typically in amounts up to 20 mol %, generally up to 5mol %, based on the vanadium catalyst, e.g., butyl perchlorocrotonate,benzoyl chloride, and other activators disclosed in Ser. Nos. 504,945and 50,946, filed May 15, 1987, the disclosures of which are herebyincorporated by reference in their entirety. Other useful catalystactivators include esters of halogenated organic acids, particularlyalkyl trichloroacetates, alkyl tribromoacetates, esters of ethyleneglycol monoalkyl (particularly monoethyl) ethers with trichloroaceticacid and alkyl perchlorocrotonates, and acyl halides. Specific examplesof these compounds include benzoyl chloride, methyl trichloroacetate,ethyl trichloroacetate, methyl tribromoacetate, ethyl tribromoacetate,ethylene glycol monoethyl ether trichloroacetate, ethylene glycolmonoethyl ether tribromoacetate, butyl perchlorocrotonate and methylperchlorocrotonate.

By practicing processes in accordance with the present invention,alpha-olefin copolymers having very narrow MWD can be made by directpolymerization. Although narrow MWD copolymers can be made using otherknown techniques, such as by fractionation or mechanical degradation,these techniques are considered to be impractical to the extent of beingunsuitable for commercial-scale operation. As regards EPM and EPDM madein accordance with the present invention, the products have good shearstability and (with specific intramolecular CD) excellent lowtemperature properties which make them especially suitable for lube oilapplications.

It is preferred that the Intra-CD of the copolymer is such that at leasttwo portions of an individual intramolecularly heterogeneous chain, eachportion comprising at least 5 weight percent of said chain, differ incomposition from one another by at least 5 weight percent ethylene. TheIntra-CD can be such that at least two portions of copolymer chaindiffer by at least 10 weight percent ethylene. Differences of at least20 weight percent, as well as, 40 weight percent ethylene are alsoconsidered to be in accordance with the present invention.

It is also preferred that the Inter-CD of the copolymer is such that 95wt. % of the copolymer chains have an ethylene composition that differsfrom the copolymer average weight percent ethylene composition by 15 wt.% or less. The preferred Inter-CD is about 13% or less, with the mostpreferred being about 10% or less.

DEGRADATION OF THE ETHYLENE AND ALPHA-OLEFIN COPOLYMER

The ethylene-α-olefin copolymers in accordance with the instantinvention are degraded to form lower molecular weight copolymers by anyof the conventional and well-known degradation or molecular weightreduction processes. By degradation or molecular weight reductionprocesses is meant processes which reduce the molecular weight of theethylene-α-olefin copolymers of this invention. These degradationprocesses are generally conventional and well known in the art. Includedamong these processes are mechanical degradation processes and thermaldegradation processes. The mechanical degradation processes generallyinvolve shear assisted breakdown of the copolymer. They may be carriedout in the presence of oxygen or in an inert atmosphere, i.e., in thesubstantial absence of oxygen. They can be conducted in the presence orabsence of catalysts and/or accelerators. While generally in mechanicalprocesses the copolymer is either in the solid or melt phase, saidprocesses may be conducted in the presence of solvent, preferably inertsolvent.

In the mechanical degradation processes the degree of shear and heatutilized in the process and the length of time that the copolymers aresubjected to said shear are those which are effective to degrade thecopolymer, i.e., reduce the molecular weight of the copolymer to thedesired molecular weight (i.e., M_(n) of about 15,000 to about 150,000)and thickening efficiency. If catalysts are utilized the amount ofcatalyst employed is a catalytic effective amount, i.e., an amounteffective to catalyze the degradation reaction.

The thermal degradation processes may be carried out in the presence ofoxygen, i.e., thermal oxidative degradation, or under an inertatmosphere, i.e., in the substantial absence of oxygen. They aregenerally, although not always, conducted on a composition comprisingthe copolymer and an inert solvent or diluent, e.g., copolymer-inertsolvent solution. Various catalysts and/or accelerators may also be usedin these thermal degradation processes.

The thermal degradation processes are carried out at temperatures andfor periods of time which are effective to degrade the copolymer, i.e.,reduce the molecular weight of the copolymer to the desired molecularweights (i.e., M_(n) of from about 15,000 to about 150,000) andthickening efficiency. If catalysts are utilized, the amount of catalystemployed is a catalytic effective amount, i.e., an amount effective tocatalyze the degradation process.

One such mechanical degradation process comprises the shear assistedoxidation or mechanical breakdown and oxidation of the copolymers in thepresence of an oxygen-containing gas such as air in a mechanical mixersuch as an extruder, masticator, Banbury mixer, rubber mill, or thelike. The mechanical breakdown and oxidation of the copolymer may bedone with a single piece of equipment, or may be done in stages withincreasing intensity of the degree of breakdown which takes place andthe amount of oxygen incorporated in the polymer. It is preferred tooperate in the absence of solvent or fluxing cyil so the polymer isreadily exposed to air. Useful equipment includes Banbury mixers andmills having adjustable gaps, which devices may be enclosed in jacketedcontainers through which a heating medium may be passed such assuperatmospheric stream or heated DOWTHERM.sub.π. When mastication orbreakdown has reached a desired level, as determined by oxygen uptakeand reduction in thickening efficiency (T.E.) as defined below, afluxing oil may be added to the degraded polymer. Usually enough oil isadded to provide a concentration of degraded polymer in the range ofabout 5 weight percent to 50 weight percent based on the weight of thetotal resulting solution. Useful temperatures for oxidatively degradingthe polymers are in the range of about 250° to 750° F. The time requiredto achieve satisfactory results will depend on the type of degrading ormastication equipment, the temperature of degrading, and particularlythe speed of rotation if using a blade mixer as the degrading ormasticating device. For example, the Bramley Beken Blade Mixer can beused in providing a single piece of equipment, the desired degree ofmastication, or milling and oxidative degradation. This mixer, which isequipped with a variable speed drive, has two rollers, fitted withhelically disposed knives geared so that one roller revolves at one-halfthe speed of the other. The rollers are journalled in a jacketed reactorhaving two hemispherical halves in its base, which conform to the radiiof the two rollers. Superheated stream, or heated DOWTHERM.sub.π, may becirculated through the jacket to provide the desired temperature.

Additionally, various catalysts and/or accelerators can be employed toaccelerate the degradation of the copolymer. The catalysts includemetals or metal salts or complexes such as copper, vanadium, chromium,manganese, nickel, iron, cobalt, molybdenum and their salts andcomplexes such as oleates, naphthenates, octoates, carboxylates,stearates and other long chain, oil soluble, organic acid salts. Othercatalysts and/or cocatalysts include the peroxides such as dibenzoylperoxide, diocyl peroxides, and dialkyl peroxides. Other suitableperoxide catalysts are disclosed in U.S. Pat. No. 3,313,793,incorporated herein by reference. One type of a catalytic, oxidative,shear accelerated process is disclosed in U.S. application Ser. No.241,620, filed Sep. 8, 1988 now U.S. Pat. No. 5,006,608 , incorporatedherein by reference.

The period of time that is generally required to achieve the desiredreduction in molecular weight and thickening efficiency will varydepending upon the temperature, RPM and horsepower of the mixer,catalyst (if any), and the amount of catalyst and accelerator used.However, a time period of about 2 minutes to about 12 hours is generallyadequate depending upon the degree to which it is desired to reduce theT.E. and molecular weight.

Another method for the mechanical degradation or shearing of theethylene-α-olefin copolymer comprises oxidizing the copolymer in aclosed vessel equipped with shearing blades. A typical apparatus of thistype is a device containing counter-rotating helical blades and known asa "Brabender Torque Rheometer". Typically, means are provided forsupplying air, oxygen, or another oxygen-containing gas to the shearingcavity of the vessel. Alternatively, or additionally, the oxygen sourcemay be a nongaseous material such as a peroxide, placed in the reactionchamber with the copolymer; this may also have a beneficial effect onthe reaction rate. It is preferred, however, that a gaseous source ofoxygen be used. Although normally an outside source of gaseous oxygen isprovided, this is not absolutely necessary. When the usual outsidesource is used, however, the gas may be supplied to the shearing cavityat any convenient flow rate. Normally, air or oxygen is provided at arate sufficient to exchange all the air or oxygen in the shearing cavityevery few seconds. Means are also provided for maintaining the shearingcavity at an elevated temperature, usually in the range of about170°-230° C. preferably 180°-225° C.

These mechanical degradation or shearing processes may also be carriedout under an inert gas or atmosphere such as nitrogen, i.e., in thesubstantial absence of oxygen.

One such shear assisted degradation carried out under an inertatmosphere may be carried out in a masticator, a rubber mill, a Banburymixer, Brabender mixers, and other mechanical mixing devices which canMix or knead the ethylene-α-olefin copolymer, rubber at elevatedtemperatures with the other components of the reaction into ahomogeneous solid rubbery mass so degradation can take place in thesolid state. Combinations of equipment may also be used, such as a lowtemperature mixer for premixing the ingredients, following which theycan be transferred to a high temperature heated mixer for degradation.

The degradation is preferably carried out using free radical initiatorssuch as peroxides, and preferably those which have a boiling pointgreater than about 100° C. Representative of these free-radicalinitiators are di-lauroyl peroxide, 2,5-di-methyl-hex-3-yne-2, 5bis-tertiary-butyl peroxide (sold as Lupersol 130) or its hexaneanalogue, di-tertiary butyl peroxide and dicumyl peroxide. The presenceof an acid, e.g. maleic anhydride, with the peroxide is preferred as itcatalyzes the decomposition of the peroxide to activate the peroxide.Other activators of the peroxide, other than acid, can be used such asthe hydroperoxides disclosed by European Published Patent Application0123424, including cumene hydroperoxide, hydrogen peroxide, tertiarybutyl hydroperoxide, etc. The initiator is generally used at a level ofbetween about 0.005% and about 1%, e.g. 0.05 to 0.5%, based on the totalweight of the olefin polymer, and temperatures of about 120° to 250° C.

The initiator degradation is preferably carried out at 120°-250° C.,more preferably 150°-220° C. An inert atmosphere, such as that obtainedby nitrogen blanketing is used. The total time for degradation and/orgrafting will usually range from about 0.005 to 12 hours. If carried outin an extruder, the total time will be relatively short, e.g. 0.005 to0.2 hours. In a masticator usually from about 0.5 to 6 hours, morepreferably 0.5 to 3 hours total time will be required. The degradationreaction will be usually carried out to at least approximately 4 times,preferably at least about 6 times the half-life of the free-radicalinitiator at the reaction temperature employed, e.g. with 2,5-dimethylhex-3-yne-2, 5-bis(t-butyl peroxide) 2 hours at 160° C. and one hour at170° C., etc.

Degradation can take place separately by heating and mixing with theinitiator, preferably under shearing stress.

Another molecular weight degradation process involves thermaldegradation of the copolymer in the absence of oxygen. One such thermaldegradation process involves heating the ethylene-α-olefin copolymer inthe presence of catalytic amount of catalyst, preferably from 0.075% to10% in the absence of oxygen to a temperature of from 275° to 450° C. orhigher, particularly when using superatmospheric pressure conditions,preferably to a temperature of from 300° to 400° C. for a period whichwill vary depending upon the temperature, catalyst and the amount ofcatalyst used, which time period is adequate to produce the desiredreduction in molecular weight. Employing catalysts in amounts and attemperatures within the upper portion of the above-mentioned respectiveranges, the time of heating can be as little as five minutes; using anamount of catalyst in the lower portion at the lower temperatures,within the aforesaid range of 0.075% to 10%, the time of heating can befrom four to five hours.

The catalysts are generally those which are known in the art for thermaldegradation processes and include: (i) an oxide or (ii) carbonate of analkali metal, alkaline earth metal, or a heavy metal, namely, antimony,bismuth, cadmium, chromium, copper, iron lead, mercury, tantalum,titanium, thallium, vanadium and zinc;.metal salts of aminocarboxylic,dicarboxylic or tricarboxylic aliphatic, phenyl or naphtyl carboxylicacid such as those disclosed in U.S. Pat. No. 3,332,926, incorporatedherein by reference; and the like.

The heating of the ploymer, catalyst mixture can be carried out in anysuitable closed equipment such as a batch reactor or continuous reactorthrough which the mixture of polymer and catalyst is passed continuouslyfor the necessary residence time to produce at the temperature ofoperation the desired lower molecular weight polyolefin. The heating canbe carried out under vacuum, at ambient pressures or undersuperatmospheric pressure conditions. In the case of batch operations atambient or superatmospheric pressure conditions, the heating can becarried out under a blanket of nitrogen or other oxygenfree atmosphere.

If desired, the mixture of catalyst and polymer can be stirred oragitated during the heating.

The thermal oxidative degradation process involves heating theehtylene-α-olefin copolymer at a temperature of at least about 100° C.in the presence of oxygen or air so as to cause degradation of thecopolymer. Such degradation is usually characterized by a substantialreduction of the molecular weight of the copolymer.

A particularly useful method of preparing the oxidized and degradedcopolymer involves heating a fluid solution of copolymer in an inertsolvent and bubbling oxygen or air through the solution at a temperatureof at least 100° C. until the desired degradation is achieved. In lieuof oxygen or air, any mixture of oxygen and inert gas such as nitrogenor carbon dioxide may be used. The inert gas thus functions as a carrierof oxygen and often provides a convenient means of introducing oxygeninto the reaction mixture.

The inert solvent useful in preparing the fluid solution of thecopolymer reactant is preferably a liquid inert hydrocarbon such asnaphtha, hexene, cyclohexene, dodecane, biphenyl, xylene or toluene. Itmay be a polar solvent such as diphenyl oxide. The amount of the solventto be used is not critical so long as a sufficient amount is used toresult in the fluid solution of the interpolymer. polymer. Such solutionusually contains from about 60 to 95% of a solvent.

The temperature at which the copolymer is oxidized and degraded is atleast about 100° C., preferably at least about 150° C. and it may be ashigh as 250° C., 300° C. or even higher.

The copolymers of the instant invention may also be degraded to lowermolecular weights by homogenization. The homogenization process isconventional and known in the art. In the homogenzation process thecopolymer, generally in a liquid state such as for example in a solutionof copolymers dissolved in a solvent such as those described above, isforced at high pressure through a device which utilizes variouslydesigned throttle valves and narrow orifices. Such a device can generatevery high shear rates. Commercial devices such as that from theManton-Gaulin Manufacturing Company or modifications thereof may beemployed. Such equipment may be operated at pressures of up to about20,000 psi to generate the necessary shear stress. The homogenizationprocess may be employed in batch or continuous mode, depending on thedegree of degradation desired.

The undegraded ethylene-alpha-olefin, preferably ethylene-propylene,copolymers are degraded to a number-average molecular weight of fromabout 15,000 to about 300,000, preferably from about 20,000 to about200,000, more preferably from about 20,000 to about 150,000.

GRAFTING MATERIALS

The materials or compounds that are grafted on the degraded ethylenecopolymers to form the grafted degraded ethylene copolymers of theinstant invention are generally those materials that can be grafted ontosaid degraded ethylene copolymers to form the grafted degraded ethylenecopolymers, which grafted degraded copolymers are then reacted with thepolyamines containing a single primary amine group and one or moretertiary amine groups to form the nitrogen containing grafted degradedethylene-alpha-olefin copolymers, preferably ethylene-propylenecopolymers, of the instant invention. These materials preferably containolefinic unsaturation and further preferably contain at least one ofcarboxylic acid moiety, ester moiety, or anhydride moiety. Theolefinically unsaturated portion, i.e., ethylenically unsaturatedportion, is one which is capable of reacting with the degraded ethylenecopolymer backbone, and upon reaction therewith becomes saturated.

These materials are generally well known in the art as graftingmaterials for conventional polyolefins such as ethylene-alpha-olefincopolymers and are generally commercially available or may be readilyprepared by well known conventional methods.

The preferred grafting materials are the carboxylic acid materials. Thecarboxylic acid material which is grafted to or reacted with thedegraded ethylene copolymer to form the grafted degraded ethylenecopolymer is preferably ethylenically unsaturated, preferablymonounsaturated, carboxylic acid material and can be either amonocarboxylic or dicarboxylic acid material. The dicarboxylic acidmaterials include (1) monounsaturated C₄ to C₁₀ dicarboxylic acidwherein (a) the carboxyl groups are vicinyl, i.e., located on adjacentcarbon atoms, and (b) at least one, preferably both, of said adjacentcarbon atoms are part of said monounsaturation; and (2) derivatives of(1) such as anhydrides or C₁ to C₅ alcohol derived mono- or diesters of(1). Upon reaction with the ethylene copolymer the monounsaturation ofthe dicarboxylic acid, anhydride, or ester becomes saturated. Thus, forexample, maleic anhydride becomes an ethylene copolymer substitutedsuccinic anhydride.

The monocarboxylic acid materials include (1) monounsaturated C₃ to C₁₀monocarboxylic acid wherein the carbon-carbon bond is conjugated to thecarboxy group, i.e., of the structure ##STR3## (2) derivatives of (1)such as C₁ to C₅ alcohol derived monoesters of (1). Upon reaction withthe ethylene copolymer, the monounsaturation of the monounsaturatedcarboxylic acid material becomes saturated. Thus, for example, acrylicacid becomes an ethylene copolymer substituted propionic acid, andmethacrylic acid becomes an ethylene copolymer substituted isobutyricacid.

Exemplary of such unsaturated mono- and dicarboxylic acids, oranhydrides and thereof include fumaric acid, itaconic acid, maleic acid,maleic anhydride, chloromaleic anhydride, acrylic acid, methacrylicacid, crotonic acid, cinnamic acid, methyl acrylate, ethyl acrylate,methyl methacrylate, etc.

Preferred carboxylic acid materials are the dicarboxylic acidanhydrides. Maleic anhydride or a derivative thereof is particularlypreferred as it does not appear to homopolymerize appreciably but graftsonto the ethylene copolymer to give two carboxylic acid functionalities.Such preferred materials have the generic formula ##STR4## wherein R'and R'' are independently hydrogen or a halogen.

Additionally, as taught by U.S. Pat. Nos. 4,160,739 and 4,161,452, bothof which are incorporated herein by reference, various unsaturatedcomonomers may be grafted on the ethylene copolymer together with theunsaturated carboxylic acid material. Such graft monomer systems maycomprise one or a mixture of comonomers different from said unsaturatedcarboxylic acid material, and which contain only one copolymerizabledouble bond and are copolymerizable with said unsaturated acidcomponent.

Typically, such comonomers do not contain free carboxylic acid groupsand are esters containing alphaethylenic unsaturation in the acid oralcohol portion; hydrocarbons, both aliphatic and aromatic, containingalpha-ethylenic unsaturation, such as the C₄ -C₁₂ alpha olefins, forexample hexane, nonene, dodecene, etc.; styrenes, for example styrene,alpha-methyl styrene, p-methyl styrene, butyl styrene, etc.; and vinylmonomers, for example vinyl acetate, vinyl chloride, vinyl ketones suchas methyl and ethyl vinyl ketone, and nitrogen containing vinyl monomersuch as vinyl pyridine and vinyl pyrrolidine, etc. comonomers containingfunctional groups which may cause crosslinking, gelation or otherinterfering reactions should be avoided, although minor amounts of suchcomonomers (up to about 10% by weight of the comonomer system) often canbe tolerated.

Specific useful copolymerizable comonomers include the following:

(A) Esters of saturated acids and unsaturated alcohols wherein thesaturated acids may be monobasic or polybasic acids containing up toabout 40 carbon atoms such as the following: acetic, propionic, butyric,valeric, caproic, stearic, oxalic, malonic, succinic, glutaric, adipic,pimelic, suberic, azelaic, sebacic, phthalic, isophthalic, terephthalic,hemimellitic, trimellitic, trimesic and the like, including mixtures.The unsaturated alcohols may be monohydroxy or polyhydroxy alcohols andmay contain up to about 40 carbon atoms, such as the following: allyl,methallyl, crotyl, 1-chloroallyl, 2-chloroallyl, cinnamyl, vinyl, methylvinyl, 1-phenallyl, butenyl, propargyl, 1-cyclohexene-3-ol, oleyl, andthe like, including mixtures.

(B) Esters of unsaturated monocarboxylic acids containing up to about 12carbon atoms such as acrylic, methacrylic and crotonic acid, and anesterifying agent containing up to about 50 carbon atoms, selected fromsaturated alcohols and alcohol epoxides. The saturated alcohols maypreferably contain up to about 40 carbon atoms and include monohydroxycompounds such as: methanol, ethanol, propanol, butanol, 2-ethylhexanol,octanol, dodecanol, cyclohexanol, cyclopentanol, neopentyl alcohol, andbenzyl alcohol; and alcohol ethers such as the mono-, methyl ormonobutyl ethers of ethylene or propylene glycol, and the like,including mixtures. The alcohol epoxides include fatty alcohol epoxides,glycidol, and various derivatives of alkylene oxides, epichlorohydrin,and the like, including mixtures.

The components of the graft copolymerizable system are used in a ratioof unsaturated carboxylic acid material monomer component to comonomercomponent of about 1:4 to 4:1, preferably about 12 to 2:1 by weight.

GRAFTING OF THE ETHYLENE COPOLYMER

Grafting of the degraded ethylene copolymer with the grafting materialmay be conducted by conventional grafting processes. The conventionalgrafting of the degraded ethylene copolymer with the grafting materialsuch as carboxylic acid material may be by any suitable and well-knownconventional method such as thermally by the "ene" reaction, usingcopolymers containing unsaturation such as ethylene-propylene-dienepolymers either chlorinated or unchlorinated, or preferably it is byfree-radical induced grafting in solvent, preferably in a minerallubricating oil as solvent.

The free-radical grafting is preferably carried out using free radicalinitiators such as peroxides, hydroperoxides, and azo compounds andpreferably those which have a boiling point greater than about 100° C.and which decompose thermally within the grafting temperature range toprovide said free radicals. The initiator is generally used at a levelof between about 0.005% and about 1%, based on the total weight of thepolymer solution, and temperatures of about 150° to 250° C., preferablyfrom about 150° C. to about 220° C. are used.

The ethylenically unsaturated carboxylic acid material, such as maleicanhydride, will generally be used in an amount ranging from about 0.01%to about 10%, preferably 0.1 to 2.0%, based on weight of the initialtotal solution. The aforesaid carboxylic acid material and free radicalinitiator are generally used in a weight percent ratio range of 1.0:1 to30:1, preferably 3.0:1 to 6:1.

In the practice of the instant invention when these ethylenicallyunsaturated grafting materials are grafted onto the aforedescribeddegraded ethylene copolymer the resultant grafted degraded copolymercontains the residue of the degraded ethylene copolymer as the backboneand the residue of the ethylenically unsaturated grafting material asthe grafted moiety. By residues is meant the respective moietiesproduced by and remaining after the grafting process or reaction. Thus,for example, while the ethylenically unsaturated grafting material maybe maleic anhydride, after the grafting reaction it is the succinicanhydride moiety that is grafted or attached to the degraded ethylenecopolymer backbone. Thus, this succinic anhydride moiety is referred toherein as the residue of the ethylenically unsaturated graftingmaterial, i.e., residue of maleic anhydride.

A preferred method of grafting is by free-radical induced grafting insolvent, preferably in a mineral lubricating oil as solvent. Thefree-radical grafting is preferably carried out using free radicalinitiators such as peroxides, hydroperoxides, and azo compounds andpreferably those which have a boiling point greater than about 100° C.and which decompose thermally within the grafting temperature range toprovide said free radicals. Representative of these free-radicalinitiators are asobutyro-nitrile, 2,5-di-methyl-hex-3-yne-2, 5bis-tertiary-butyl peroxide (sold as Lupersol 130) or its hexaneanalogue, di-tertiary butyl peroxide and dicumyl peroxide. The initiatoris generally used at a level of between about 0.005% and about 1%, basedon the total weight of the polymer solution, and temperatures of about150° to 220° C.

The initiator grafting is preferably carried out in an inert atmosphere,such as that obtained by nitrogen blanketing. While the grafting can becarried out in the presence of air, the yield of the desired graftpolymer is generally thereby decreased as compared to grafting under aninert atmosphere substantially free of oxygen. The grafting time willusually range from about 0.1 to 12 hours, preferably from about 0.5 to 6hours, more preferably 0.5 to 3 hours. The graft reaction will beusually carried out to at least approximately 4 times, preferably atleast about 6 times the half-life of the free-radical initiator at thereaction temperature employed, e.g. with 2,5-dimethyl hex-3-yne-2,5-bis(t-butyl peroxide) 2 hours at 160° C. and one hour at 170° C., etc.

In the grafting process, usually the copolymer solution is first heatedto grafting temperature and thereafter said grafting material such asunsaturated carboxylic acid material and initiator are added withagitation, although they could have been added prior to heating. Whenthe reaction is complete, the excess grafting material can be eliminatedby an inert gas purge, e.g. nitrogen sparging. Preferably the graftingmaterial such as carboxylic acid material that is added is kept belowits solubility limit in the polymer solution, e.g. below about 1 wt. %,preferably below 0.4 wt. % or less, of free maleic anhydride based onthe total weight of polymer-solvent solution, e.g. ethylene copolymermineral lubricating oil solution. Continuous or periodic addition of thegrafting material such as carboxylic acid material along with anappropriate portion of initiator, during the course of the reaction, canbe utilized to maintain the grafting material such as carboxylic acidmaterial below its solubility limits, while still obtaining the desireddegree of total grafting.

In the initiator grafting step the maleic anhydride or other carboxylicacid material used will be grafted onto both the degraded copolymer andthe solvent for the reaction. Many solvents such as dichlorobenzene arerelatively inert and may be only slightly grafted, while mineral oilwill tend to be more grafted. The exact split of graft between thesubstrate present depends upon the polymer and its reactivity, thereactivity and type of oil, the concentration of the polymer in the oil,and also upon the maintenance of the carboxylic acid material insolution during the course of the reaction and minimizing the presenceof dispersed, but undissolved acid, e.g. the maleic anhydride. Theundissolved acid material appears to have an increased tendency to reactto form oil insoluble materials as opposed to dissolved acid material.The split between grafted oil and grafted polymer may be measuredempirically from the infrared analyses of the product dialyzed into oiland polymer fractions.

The grafting is preferably carried out in a mineral lubricating oilwhich need not be removed after the grafting step but can be used as thesolvent in the subsequent reaction of the graft polymer with thepolyamine containing one primary amine group and one or more tertiaryamine groups and as a solvent for the end product to form thelubricating additive concentrate.

The amount of grafting material such as carboxylic acid material used inthe grafting reaction is an amount which is effective to provide agrafted degraded ethylene copolymer which upon further reaction with thepolyamine containing one primary amine group and at least one tertiaryamine group as described hereinafter provides a material exhibiting theproperties of a multifunctional viscosity index improver additive, morespecifically a viscosity index improver-dispersant additive, i.e., amaterial having both V.I. improving and dispersancy properties in anoleaginous composition. That is to say, an amount which is effective toprovide, upon reaction of the grafted degraded ethylene copolymer withthe polyamine, an oleaginous composition exhibiting improvedviscometric, particularly low temperature viscometric, and dispersancyproperties. Generally, this amount of grafting material, e.g., moles ofcarboxylic acid material such as maleic anhydride, is an amount which iseffective to provide a grafted degraded ethylene copolymer, e.g.,ethylene-alpha-olefin substituted carboxylic acid material such asethylene- propylene substituted succinic anhydride, containing anaverage number of acid material moieties, e.g., succinic anhydride,grafted to or present on a 10,000 number average molecular weightsegment of a mole of degraded ethylene copolymer of at least about 0.1,preferably at least about 0.5, and more preferably at least about 1. Themaximum average number of grafted moieties present per 10,000 averagenumber molecular weight segment of a mole of degraded ethylene copolymerbackbone should not exceed about 10, preferably about 7 and morepreferably about 5. Preferably, the average number, moles, of graftedmoieties present per mole of ethylene copolymer backbone is at leastabout 0.6, preferably at least about 0.8, and more preferably at leastabout 1. Preferably, the maximum average number of grafted moietiesgrafted to or present per mole of degraded ethylene copolymer backboneshould generally not exceed about 10, preferably about 7, and morepreferably about 5. Thus, for example, a mole of grafted degradedethylene copolymer, e.g., ethylene-propylene substituted succinicanhydride, containing a degraded ethylene copolymer backbone such as adegraded ethylene-propylene backbone having an average number molecularweight of 50,000 contains grafted to said backbone an average number ofsuccinic anhydride moieties of from about 0.5 to about 50, preferablyfrom about 0.6 to about 10. Typically, from about 0.2 to about 12,preferably from about 0.4 to about 6 moles of said carboxylic acidmaterial are charged to the reactor per mole of degraded ethylenecopolymer charged.

Normally, not all of the degraded ethylene copolymer reacts with thecarboxylic acid material, e.g., maleic anhydride, to produce a grafteddegraded ethylene copolymer, e.g., ethylene-propylene substitutedsuccinic anhydride. The resultant reaction product mixture, therefore,contains reacted or grafted ethylene copolymer, e.g., ethylene-propylenesubstituted succinic anhydride unreacted or ungrafted ethylenecopolymer, and unreacted grafting material, e.g., maleic anhydride. Theunreacted ethylene copolymer is typically not removed from the reactionproduct mixture, and the reaction product mixture, generally stripped ofany unreacted grafting material, is utilized as is or is employed forfurther reaction with the amine as described hereinafter.

Characterization of the average number of moles of grafting materialsuch as carboxylic acid material, e.g., maleic anhydride, which havereacted per mole of degraded ethylene copolymer charged to the reaction(whether it has undergone reaction or not) is defined herein as theaverage number of grafted moieties grafted to or present per mole ofethylene copolymer the resulting reaction product mixture can besubsequently modified, i.e., increased or decreased by techniques knownin the art, such modifications do not alter the average number ofgrafted moieties as defined above. The term grafted degraded ethylenecopolymer is intended to refer to the reaction product mixture whetherit has undergone such modification or not.

The grafted, preferably acid material grafted, degraded ethylenecopolymer is reacted with the polyamine containing one primary aminogroup and at least one tertiary amino group to form the nitrogencontaining grafted degraded ethylene copolymers of the instantinvention.

THE POLYAMINES

The amine reactants which are reacted with the grafted degraded ethylenecopolymer to form the multifunctional viscosity index improver of theinstant invention are amine compounds containing only one primary aminegroup. These amine compounds contain, in addition to the single primaryamine group, at least one tertiary amine group and no secondary aminegroups.

The mono-primary amine containing compounds of the present invention canbroadly be represented by the formula R'--NH₂ where R' is an alkyl, acycloalkyl, an aromatic, and combinations thereof, e.g., an alkylsubstituted cycloalkyl. Furthermore, R' can be an alkyl, an aromatic, acycloalkyl group, or combination thereof containing one or more tertiaryamine groups therein. R' can also be an alkyl, a cycloalkyl, an aromaticgroup or combinations thereof containing one or more heteroatoms (forexample oxygen, nitrogen, sulfur, etc.). R' can further be an alkyl, acycloalkyl, an aromatic, or combinations thereof containing sulfide oroxy linkages therein.

The mono- primary amine containing compounds are those that, in additionto the single primary amine group, contain at least one tertiary aminegroup and no secondary amine groups, i.e., R' contains at least onetertiary amine group. These types of primary amine containing compoundsmay be referred to as polyamines.

These types of polyamines are well known in the art and some of saidpolyamines are disclosed, inter alia, in U.S. Pat. Nos. 3,239,658;3,449,250 and 4,171,273, all of which are incorporated herein byreference.

These polyamines include those represented by the general formulae:##STR5## Generally R' contains from 1 to 50 carbon atoms, e.g., an alkylcontaining from 1 to 50 carbon atoms, a cycloalkyl containing from 5 toabout 12 ring carbon atoms, and an aromatic radical such as aryl,aralkyl or alkaryl containing from 6 to about 12 ring carbon atoms.wherein:

p is zero or one;

s is zero or one;

t is 1 to about 10;

R¹ and R² are independently selected from alkyl radicals, eitherstraight chain or branched, containing from 1 to about 6 carbon atomsand cycloalkyl radicals containing from 4 to about 8 ring carbon atoms;

R³ and R⁶ are independently selected from unsubstituted or C₁ -C₆ alkylsubstituted alkylene radicals having from 1 to about 6 carbon atoms;

R⁴ and R⁵ are independently selected from unsubstituted, C₁ -C₆ alkylsubstituted, or Y substituted alkylene radicals containing from 1 toabout 6 carbon atoms, or from unsubstituted, C₁ -C₆ alkyl substituted,or Y substituted alkenylene radicals containing from 2 to about 6 carbonatoms;

R⁷ is hydrogen, alkyl radical containing from 1 to about 6 carbons,##STR6## with the proviso that if a s is zero then R⁷ is not hydrogen;X¹ and X² are independently selected from --O--, --S--, >NR¹, >R³, --NY,or CHY radicals; and

Y is --NH₂ or --R³ --NH₂ ;

with the proviso that the identities of groups X¹, X², R⁴ and R⁵ areselected to provide only one primary amine group and at least onetertiary amine per molecule of structural Formula III, i.e., themolecule of structural formula III contains one and only one Y group.

In compounds of Formula III it is generally preferred that R⁴ and R⁵ arealkylene rather than alkenylene radicals.

Some illustrative non-limiting examples of the mono-primary aminecontaining compounds include: N,N-dimethyl-1,2-ethylenediamine;N-methyl-N-ethyl-1,2-propylenediamine;N,N-dimethyl-1,3-propylenediamine; N,N-diethyl-1,3-propylenediamine;N,N-dipropyl-1,3-propylenediamine; N,N-diisopropyl-1,3-propylenediamine;N,N-dibutyl-1,3-propylenediamine; N,N-diisobutyl-1,3-propylenediamine;N,N-(di-t-butyl)-1,3-propylenediamine;N,N-dimethyl-N'-ethyl-1,3-propylenediamine;N,N-dimethyl-N'-butyl1,3-propylenediamine;N,N-dimethyl-1,2-isopropylenediamine; N,N-dimethyl-1,4-butylenediamine;N,N-diethyl-2,3-butylenediamine; N,N-dimethyl-1,3-isobutylenediamine;N,N-dimethyl-1,3-butylenediamine; N,N-dimethyl-1,3-t-butylenediamine;N,N-dicyclohexyl-1,3-propylenediamine;N,N-dicyclohexyl-1,2-ethylenediamine, 2-aminopyridine, aminopyrazine,N-(3-aminopropyl) morpholine, N-(3-aminopropyl) imidazole andN-(2-aminoethyl)pyrrolidine, N,N-dimethylhydrazine, methylamine,ethylamine, butylamine, 2-methyoxyethylamine, 3-alkoxypropylamineswherein the alkoxy group contains from 1 to 18 carbon atoms, usually analkoxy group having from 1 to 8 carbon atoms and has the formulaR''--O--CH₂ CH₂ C--H₂ --NH₂, such as 3-methoxypropylamine,3-isobutyoxypropylamine and 3-(alkoxypoly, ethoxy)-propylamines havingthe formula R''O(CH₂ C--H₂ O)_(x) --CH₂ CH₂ CH₂ NH₂ wherein the alkoxygroup is as immediately set forth above and where x is 1 to 50,4,7-dioxaoctylamine, N-(3-aminopropyl)-N¹ -methylpiperazine,N-(2-aminoethyl)piperazine, (2-aminoethyl)-pytidines, aminopyridines,2-aminomethylpyridines, 2-aminomethylfuran,3-amino-2-oxotetrahydrofuran, 2-aminomethypyrrolidine,1-methyl-2-aminomethylpyrrolidine, 1-aminopyrrolidine,1-(3-aminopropyl)-2-methypiperidine, 4-aminomethylpiperidine,N-(2-aminoethyl)morpholine, i-ethyl-3-aminopiperidine,1-aminopiperidine, N-aminomorpholine, and the like.

It is to be understood that only one amine compound can be reacted withthe grafted degraded ethylene copolymer or a mixture of two or moredifferent amine compounds can be utilized.

REACTION OF GRAFTED DEGRADED ETHYLENE COPOLYMER WITH POLYAMINE

The grafted degraded ethylene copolymer, preferably in solution, such asan oil solution, containing 5 to 95 wt. %, preferably 5 to 30 wt. %, andmore preferably 10 to 20 wt. % of said grafted degraded ethylenecopolymer, is readily reacted by introducing the polyamine containingone primary amine group and one or more tertiary amine groups into saidgrafted degraded ethylene copolymer containing solution and heating at atemperature of from about 100° C. to 250° C., preferably from 125° to175° C., for from about 1 to 10 hours, usually about 2 to about 6 hours.The heating is preferably carried out, in the case of degraded ethylenecopolymer substituted dicarboxylic acid material, to favor formation ofimides rather than amides and salts. In the case of degraded ethylenecopolymer substituted monocarboxylic acid material heating is preferablycarried out to favor formation of amides rather than salts. Removal ofwater assures completion of the imidation/ amidation reaction. Reactionratios can vary considerably, depending upon the reactants, amounts ofexcess, type of bonds formed, etc. Generally, from about 1 to 5,preferably from about 1.5 to 3 moles of degraded ethylene copolymersubstituted monocarboxylic or dicarboxylic acid moiety content, e.g.,grafted succinic anhydride content, is used per equivalent of polyaminereactant, e.g., amine.

Preferably, the degraded ethylene copolymer substituted mono- ordicarboxylic acid material and polyamine will be contacted for a timeand under conditions sufficient to react substantially all of theprimary nitrogens in the polyamine reactant. The progress of thisreaction can be followed by infra-red analysis.

This reaction can be conducted in a polar or non-polar solvent, e.g.,xylene, toluene, benzene, and the like, and is preferably conducted inthe presence of a mineral or synthetic lubricating oil.

Further aspects of the present invention reside in the formation ofmetal complexes and other post-treatment derivatives, e.g., boratedderivatives, of the nitrogen containing grafted degraded ethylenecopolymers prepared in accordance with this invention. Suitable metalcomplexes may be formed in accordance with known techniques of employinga reactive metal ion species during or after, preferably after, theformation of the nitrogen containing grafted degraded ethylenecopolymers of this invention. Complex-forming metal reactants includethe nitrates, thiocyanates, halides, carboxylates, phosphates,thio-phosphates, sulfates, and borates of transition metals such asiron, cobalt, nickel, copper, chromium, manganese, molybdenum, tungsten,ruthenium, palladium, platinum, cadmium, lead, silver, mercury, antimonyand the like. Prior art disclosures of these complexing reactions may befound in U.S. Pat. No. 3,306,908 and Re. 26,443, both incorporatedherein by reference.

Post-treatment compositions include those formed by reacting thenitrogen containing grafted degraded ethylene copolymers of the presentinvention with one or more post-treating reagents, usually selected fromthe group consisting of boron oxide, boron oxide hydrate, boron halides,boron acids, esters of boron acids, carbon disulfide, sulfur, sulfurchlorides, alkenyl cyanides, aldehydes, ketones, urea, thio-urea,guanidine, dicyanodiamide, hydrocarbyl phosphates, hydrocarbylphosphites, hydrocarbyl thiophosphates, hydrocarbyl thiophosphites,phosphorus sulfides, phosphorus oxides, phosphoric acid, hydrocarbylthiocyanates, hydrocarbyl isocyanates, hydrocarbyl isothiocyanates,epoxides, episulfides, formaldehyde or formaldehyde-producing compoundsplus phenols, sulfur plus phenols, and carboxylic acid or anhydrideacylating agents. The reaction of such posttreating agents with thenitrogen containing grafted degraded ethylene copolymers of thisinvention is carried out using procedures known in the art. For example,boration may be accomplished in accordance with the teaching of U.S.Pat. No. 3,254,025 by treating the nitrogen containing grafted degradedcopolymer of the present invention with a boron oxide, halide, ester oracid. Treatment may be carried out by adding about 1-3 wt % of the boroncompound, preferably boric acid, and heating and stirring the reactionmixture at about 135° C. to 165° C. for 1 to 5 hours followed bynitrogen stripping and filtration, if desired. Mineral oil or inertorganic solvents facilitate the process.

Since post-treating processes involving the use of these post-treatingreagents are known insofar as application to conventional nitrogencontaining grafted ethylene copolymers detailed descriptions of theseprocesses herein are unnecessary. In order to apply these processes tothe compositions of this invention, all that is necessary is thatreaction conditions, ratio of reactants, and the like as described inthe prior art, be applied to the novel compositions of this invention.The following U.S. patents are expressly incorporated herein byreference for their disclosure of post-treating processes andpost-treating reagents applicable to the compositions of this invention:U.S. Pat. Nos. 3,087,936; 3,200,107; 3,254,025; 3,256,185; 3,278,550;3,281,428; 3,282,955; 3,284,410; 3,338,832, 3,344,069; 3,366,569;3,373,111; 3,367,943; 3,403,102; 3,428,561; 3,502,677; 3,513,093;3,533,945; 3,541,012; 3,639,242; 3,708,522; 3,859,318; 3,865,813;3,470,098; 3,369,021; 3,184,411; 3,185,645; 3,245,908; 3,245,909;3,245,910; 3,573,205; 3,692,681; 3,749,695; 3,865,740; 3,954,639;3,458,530; 3,390,086; 3,367,943; 3,185,704, 3,551,466; 3,415,750;3,312,619; 3,280,034; 3,718,663; 3,652,616; UK Pat. No. 1,085,903; UKPat. No. 1,162,436; U.S. Pat. No. 3,558,743. The processes of theseincorporated patents, as applied to the compositions of this invention,and the post-treated compositions thus produced constitute a furtheraspect of this invention.

A minor amount, e.g. 0.001 up to 49 wt %, based on the weight of thetotal composition, of the oil-soluble nitrogen containing grafteddegraded ethylene copolymers produced in accordance with this inventioncan be incorporated into a major amount of an oleaginous material, suchas a lubricating oil or hydrocarbon fuel, depending upon whether one isforming finished products or additive concentrates. The amount of themultifunctional viscosity index improving or modifying nitrogencontaining grafted degraded ethylene alpha-olefin copolymer of thepresent invention present in an oleaginous composition such as alubricating oil composition, e.g., fully formulated lubricating oilcomposition, is an amount which is effective to improve or modify theviscosity index of said oil composition, i.e., a viscosity improvingeffective amount or an amount effective to improve the viscometricproperties and provide dispersancy to said composition, i.e., aviscosity improving and dispersant effective amount. Generally, thisamount is from about 0.001 to about 20 wt. %, preferably from about 0.01to about 15 wt. %, and more preferably from about 0.1 to about 10 wt. %,based on the weight of the total composition.

The lubricating oils to which the products of this invention can beadded include not only hydrocarbon oil derived from petroleum, but alsoinclude synthetic lubricating oils such as esters of dibasic acids;complex esters made by esterification of monobasic acids, polyglycols,dibasic acids and alcohols, polyolefin oils, etc.

The nitrogen containing grafted degraded ethylene copolymers of thisinvention may be utilized in a concentrate form, e.g., from about 2 wt %up to about 49 wt. %, preferably 3 to 25 wt. %, in oil, e.g., minerallubricating oil, for ease of handling, and may be prepared in this formby carrying out the reaction of the invention in oil as previouslydiscussed.

The above oil compositions may optionally contain other conventionaladditives, such as for example, pour point depressants, antiwear agents,antioxidants, viscosity-index improvers, dispersants, corrosioninhibitors, anti-foaming agents, detergents, rust inhibitors, frictionmodifiers, and the like.

Corrosion inhibitors, also known as anti-corrosive agents, reduce thedegradation of the metallic parts contacted by the lubricating oilcomposition. Illustrative of corrosion inhibitors are phosphosulfurizedhydrocarbons and the products obtained by reaction of aphosphosulfurized hydrocarbon with an alkaline earth metal oxide orhydroxide, preferably in the presence of an alkylated phenol or of analkylphenol thioester, and also preferably in the presence of carbondioxide. Phosphosulfurized hydrocarbons are prepared by reacting asuitable hydrocarbon such as a terpene, a heavy petroleum fraction of aC₂ to C₆ olefin polymer such as polyisobutylene, with from 5 to 30 wt. %of a sulfide of phosphorus for 1/2 to 15 hours, at a temperature in therange of about 66° to about 316° C. Neutralization of thephosphosulfurized hydrocarbon may be effected in the manner taught inU.S. Pat. No. 1,969,324.

Oxidation inhibitors, or antioxidants, reduce the tendency of mineraloils to deteriorate in service which deterioration can be evidenced bythe products of oxidation such as sludge and varnish-like deposits onthe metal surfaces, and by viscosity growth. Such oxidation inhibitorsinclude alkaline earth metal salts of alkylphenolthioesters havingpreferably C₅ to C₁₂ alkyl side chains, e.g., calcium nonylphenolsulfide, barium toctylphenyl sulfide, dioctylphenylamine,phenylalphanaphthylamine, phospho- sulfurized or sulfurizedhydrocarbons, etc.

Other oxidation inhibitors or antioxidants useful in this inventioncomprise oil-soluble copper compounds. The copper may be blended intothe oil as any suitable oil-soluble copper compound. By oil soluble itis meant that the compound is oil soluble under normal blendingconditions in the oil or additive package. The copper compound may be inthe cuprous or cupric form. The copper may be in the form of the copperdihydrocarbyl thio- or dithio-phosphates. Alternatively, the copper maybe added as the copper salt of a synthetic or natural carboxylic acid.Examples of same thus include C₁₀ to C₁₈ fatty acids, such as stearic orpalmitic acid, but unsaturated acids such as oleic or branchedcarboxylic acids such as napthenic acids of molecular weights of fromabout 200 to 500, or synthetic carboxylic acids, are preferred, becauseof the improved handling and solubility properties of the resultingcopper carboxylates. Also useful are oil-soluble copper dithiocarbamatesof the general formula (RR,NCSS)nCu (where n is 1 or 2 and R and R, arethe same or different hydrocarbyl radicals containing from 1 to 18, andpreferably 2 to 12, carbon atoms, and including radicals such as alkyl,alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic radicals.Particularly preferred as R and R, groups are alkyl groups of from 2 to8 carbon atoms. Thus, the radicals may, for example, be ethyl, n-propyl,i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-heptyl,n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl,cyclohexyl, methylcyclopentyl, propenyl, butenyl, etc. In order toobtain oil solubility, the total number of carbon atoms (i.e., R and R,)will generally be about 5 or greater. Copper sulphonates, phenates, andacetylacetonates may also be used.

Exemplary of useful copper compounds are copper CUI and/or CUII salts ofalkenyl succinic acids or anhydrides. The salts themselves may be basic,neutral or acidic. They may be formed by reacting (a) polyalkylenesuccinimides (having polymer groups of M_(n) of 700 to 5,000) derivedfrom polyalkylene-polyamines, which have at least one free carboxylicacid group, with (b) a reactive metal compound. Suitable reactive metalcompounds include those such as cupric or cuprous hydroxides, oxides,acetates, borates, and carbonates or basic copper carbonate.

Examples of these metal salts are Cu salts of polyisobutenyl succinicanhydride, and Cu salts of polyisobutenyl succinic acid. Preferably, theselected metal employed is its divalent form, e.g., Cu+2. The preferredsubstrates are polyalkenyl succinic acids in which the alkenyl group hasa molecular weight greater than about 700. The alkenyl group desirablyhas a M_(n) from about 900 to 1,400, and up to 2,500, with a M_(n) ofabout 950 being most preferred. Especially preferred is polyisobutylenesuccinic anhydride or acid. These materials may desirably be dissolvedin a solvent, such as a mineral oil, and heated in the presence of awater solution (or slurry) ok the metal bearing material. Heating maytake place between 70° and about 200° C. Temperatures of 110° C. to 140°C. are entirely adequate. It may be necessary, depending upon the saltproduced, not to allow the reaction to remain at a temperature aboveabout 140° C. for an extended period of time, e.g., longer than 5 hours,or decomposition of the salt may occur.

The copper antioxidants (e.g., Cu-polyisobutenyl succinic anhydride,Cu-oleate, or mixtures thereof) will be generally employed in an amountof from about 50 to 500 ppm by weight of the metal, in the finallubricating or fuel composition.

Friction modifiers serve to impart the proper friction characteristicsto lubricating oil compositions such as automatic transmission fluids.

Representative examples of suitable friction modifiers are found in U.S.Pat. No. 3,933,659 which discloses fatty acid esters and amides; U.S.Pat. No. 4,176,074 which describes molybdenum complexes ofpolyi-sobutenyl succinic anhydride-amino alkanols; U.S. Pat. No.4,105,571 which discloses glycerol esters of dimerized fatty acids; U.S.Pat. No. 3,779,928 which discloses alkane phosphonic acid salts; U.S.Pat. No. 3,778,375 which discloses reaction products of a phosphonatewith an oleamide; U.S. Pat. No. 3,852,205 which disclosesS-carboxyalkylene hydrocarbyl succinimide, S-carboxyalkylene hydrocarbylsuccinamic acid and mixtures thereof; U.S. Pat. No. 3,879,306 whichdiscloses N(hydroxyalkyl)alkenyl-succinamic acids or succinimides; U.S.Pat. No. 3,932,290 which discloses reaction products of di- (loweralkyl) phosphites and epoxides; and U.S. Pat. No. 4,028,258 whichdiscloses the alkylene oxide adduct of phosphosulfurizedN-(hydroxyalkyl) alkenyl succinimides. The disclosures of the abovereferences are herein incorporated by reference. The most preferredfriction modifiers are succinate esters, or metal salts thereof, ofhydrocarbyl substituted succinic acids or anhydrides andthiobis-alkanols such as described in U.S. Pat. No. 4,344,853.

Dispersants maintain oil insolubles, resulting from oxidation duringuse, in suspension in the fluid thus preventing sludge flocculation andprecipitation or deposition on metal parts. Suitable dispersants includehigh molecular weight alkyl succinimides, the reaction product ofoil-soluble polyisobutylene succinic anhydride with ethylene amines suchas tetraethylene pentamine and borated salts thereof.

Pout point depressants, otherwise known as lube oil flow improvers,lower the temperature at which the fluid will flow or can be poured.Such additives are well known. Typically of those additives whichusefully optimize the low temperature fluidity of the fluid are C₈ -C₁₈dialkylfumarate vinyl acetate copolymers, polymethacrylates, and waxnaphthalene. Foam control can be provided by an antifoamant of thepolysiloxane type, e.g., silicone oil and polydimethyl siloxane.

Anti-wear agents, as their name implies, reduce wear of metal parts.Representatives of conventional antiwear agents are zincdialkyldithiophosphate and zinc diaryldithiosphate.

Detergents and metal rust inhibitors include the metal salts ofsulphonic acids, alkyl phenols, sulfurized alkyl phenols, alkylsalicylates, naphthenates and other oil soluble mono- and dicarboxylicacids. Highly basic (viz, overbased) metal sales, such as highly basicalkaline earth metal sulfonates (especially Ca and Mg salts) arefrequently used as detergents. Representative examples of suchmaterials, and their methods of preparation, are found in co-pendingSer. No. 754,001, filed Jul. 11, 1985 now abandoned, the disclosure ofwhich is hereby incorporated by reference.

Some of these numerous additives can provide a multiplicity of effects,e.g., a dispersant-oxidation inhibitor. This approach is well known andneed not be further elaborated herein.

Compositions when containing these conventional additives are typicallyblended into the base oil in amounts which are effective to providetheir normal attendant function. Representative effective amounts ofsuch additives are illustrated as follows:

    ______________________________________                                                          Wt. % a.i.                                                                              Wt. % a.i.                                        Additive          (Broad)   (Preferred)                                       ______________________________________                                        Viscosity Modifier                                                                               .01-12   .01-4                                             Corrosion Inhibitor                                                                             0.01-5    .01-1.5                                           Oxidation Inhibitor                                                                             0.01-5    .01-1.5                                           Dispersant         0.1-20   0.1-8                                             Pour Point Depressant                                                                           0.01-5    .01-1.5                                           Anti-Foaming Agents                                                                             0.001-3   .001-0.15                                         Anti-Wear Agents  0.001-5   .001-1.5                                          Friction Modifiers                                                                              0.01-5    .01-1.5                                           Detergents/Rust Inhibitors                                                                       .01-10   .01-3                                             Mineral Oil Base  Balance   Balance                                           ______________________________________                                    

When other additives are employed, it may be desirable, although notnecessary, to prepare additive concentrates comprising concentratedsolutions or dispersions of the multifunctional viscosity indeximprovers of the instant invention index (in concentrate amountshereinabove described), together with one or more of said otheradditives (said concentrate when constituting an additive mixture beingreferred to here in as an additive package) whereby several additivescan be added simultaneously to the base oil to form the lubricating oilcomposition. Dissolution of the additive concentrate into thelubricating oil may be facilitated by solvents and by mixing accompaniedwith mild heating, but this is not essential. The concentrate oradditive-package will typically be formulated to contain the dispersantadditive and optional additional additives in proper amounts to providethe desired concentration in the final formulation when theadditive-package is combined with a predetermined amount of baselubricant. Thus, the products of the present invention can be added tosmall amounts of base oil or other compatible solvents along with otherdesirable additives to form additive-packages containing activeingredients in collective amounts of typically from about 2.5 to about90%, and preferably from about 5 to about 75%, and most preferably fromabout 8 to about 50% by weight additives in the appropriate proportionswith the remainder being base oil.

The final formulations may employ typically about 10 wt. % of theadditive-package with the remainder being base oil.

All of said weight percents expressed herein are based on activeingredient (a.i.) content of the additive, and/or upon the total weightof any additive-package, or formulation which will be the sum of thea.i. weight of each additive plus the weight of total oil or diluent.

As mentioned hereinafore the nitrogen containing grafted degradedethylene copolymers of the present invention are particularly useful asfuel and lubricating oil additives.

The nitrogen containing grafted degraded ethylene copolymers of thisinvention find their primary utility, however, in lubricating oilcompositions, which employ a base oil in which these copolymers aredissolved or dispersed.

Thus, base oils suitable for use in preparing the lubricatingcompositions of the present invention include those conventionallyemployed as crankcase lubricating oils for spark-ignited andcompression-ignited internal combustion engines, such as automobile andtruck engines, marine and railroad diesel engines, and the like.Advantageous results are also achieved by employing the additives of thepresent invention in base oils conventionally employed in and/or adaptedfor use as power transmitting fluids such as automatic transmissionfluids, tractor fluids, universal tractor fluids and hydraulic fluids,heavy duty hydraulic fluids, power steering fluids and the like. Gearlubricants, industrial oils, pump oils and other lubricating oilcompositions can also benefit from the incorporation therein of theadditives of the present invention.

Thus, the additives of the present invention may be suitablyincorporated into synthetic base oils such as alkyl esters ofdicarboxylic acids, polyglycols and alcohols; polyalpha-olefins,polybutenes, alkyl benzenes, organic esters of phosphoric acids,polysilicone oils, etc.

The nitrogen containing grafted degraded ethylene copolymers of theinstant invention are oil-soluble, dissolvable in oil with the aid of asuitable solvent, or are stably dispersible therein. Oil-soluble,dissolvable, or stably dispersible as that terminology is used hereindoes not necessarily indicate that the materials are soluble,dissolvable, miscible, or capable of being suspended in oil in allproportions. It does mean, however, that the additives for instance, aresoluble or stably dispersible in oil to an extent sufficient to exerttheir intended effect in the environment in which the oil is employed.Moreover, the additional incorporation of other additives may alsopermit incorporation of higher levels of a particular copolymer hereof,if desired.

Accordingly, while any effective amount, i.e., viscosity index improvingor viscosity index improvingdispersant effective amount, of theadditives of the present invention can be incorporated into the fullyformulated lubricating oil composition, it is contemplated that sucheffective amount be sufficient to provide said lube oil composition withan amount of the additive of typically from about 0.001 to about 20,preferably 0.01 to 15, more preferably from 0.1 to about 10 and mostpreferably from about 0.25 to about 5 wt. %, based on the weight of saidcomposition.

The following examples further illustrate the present invention. Theexamples are presented by way of illustration and do not limit theinvention thereto. Unless otherwise indicated, all parts and percentagesare on a weight basis.

EXAMPLE 1

An ethylene-propylene copolymer having an ethylene content of about 56wt. %, a Thickening Efficiency (T.E.) of about 2.6, a Shear StabilityIndex (SSI) of about 50%, an M_(w) of about 180,000, an M_(n) of about112,000, a M_(w) /M_(n) of 1.6, and M_(z) /M_(w) of 1.2 is prepared in atubular reactor under the following conditions:

    ______________________________________                                        Reactor Inlet Temp. (°F.)                                                                 33                                                         Reactor Outlet Temp. (°F.)                                                                128                                                        Sidestream Feed Temp. (°F.)                                                               26                                                         Catalyst Premix Temp. (°F.)                                                               37                                                         Reactor Residence Time (Sec.)                                                                    7.7/7.7/32.4/14.4/16.9/20.7                                at Sidestream 1/2/3/4/5/6                                                     Inlet Feed Rates (Klb./hr.)                                                   Hexane             177                                                        Ethylene              1.06                                                    Propylene            18.2                                                     VCl.sub.4             6.042                                                   Al.sub.2 (C.sub.2 H.sub.5).sub.3 Cl.sub.3                                                           1.09                                                    Sweep Hexane         9.9                                                      Sidestream Feed Rates (Klb./hr.)                                              Hexane             88                                                         Ethylene             8.8                                                      Propylene          14                                                         Total Hexane (Klb./hr.)                                                                          275                                                        Sidestream Feed Splits (wt. %)                                                Sidestream 1/2/3/4/5/6                                                                           7.7/7.7/32.4/14.4/16.9/20.7                                ______________________________________                                    

About three hundred grams of this ethylene-propylene copolymer aremasticated under an air atmosphere at 150° C. for a period of aboutthree and three quarter hours in a laboratory masticator. The resultantdegraded copolymer has a T.E. of about 1.55, M_(w) of about 71,300, anda M_(z) /M_(w) of 1.52.

Sixty grams of this degraded copolymer are dissolved in 240 grams ofSLOONLP mineral oil in a reactor flask under a nitrogen atmosphere whileheating to 175° C. to make a 20 wt. % copolymer solution. Six grams ofmaleic anhydride are charged to the reactor in 4 equal portions, eachportion consisting of 1.5 grams of maleic anhydride. After each chargeof maleic anhydride 0.15 gram of di-t-butyl peroxide initiator arecharged to the reactor (total charge amount of di-t-butyl peroxidecharged to the reactor is 0.6 grams). The resulting reaction mixture isreacted at 175° C. under a nitrogen atmosphere for 1/2 hour. Thereaction mixture is then stripped with nitrogen for 15 minutes to removeremaining unreacted maleic anhydride. The maleic anhydride functionality(total acidity) is determined to be 0.107 meq/g. by standard acid-basetitration.

Into a reactor vessel are placed 130 grams of this succinic anhydridegrafted degraded ethylene-propylene reaction product composition(grafted degraded copolymer in oil solution). This solution is thenheated to 175° C. under a nitrogen atmosphere. To this reaction solutionare added 2.25 grams of N-aminopropylmorpholine over a 5-minute period.This reaction mixture is then soaked at 175° C. for 30 minutes. Thereaction mixture is then stripped with nitrogen for 30 minutes. The SSIof the nitrogen containing grafted degraded ethylene-propylene copolymeris determined to be 15.3%.

A SAE 1OW40 viscosity grade lubricating oil composition containing 13.75wt. % of the reaction product containing composition prepared asdescribed above and a conventional detergent inhibitor package isprepared. The KV at 100° C. in centistokes, CCS, TP-1 and MRV of thislubricating oil composition are determined and the results are set forthin Table 1.

MRV (Mini Rotary Viscometer), is determined using a technique describedin ASTM-D3829, and measures viscosity in centipoise. MRV was determinedat -25° C.

CCS (Cold Cranking Simulator), is determined-using a technique describedin SAE J300 Appendix, and is a high shear viscosity measurement incentipoise. This test is related to a lubricating oil's resistance tocold engine starting. The higher the CCS, the greater the oil'sresistance to cold engine starting.

TP-1 is determined using a technique described in ASTM-D4684. This isessentially the same as the MRV noted above except that a slow coolingcycle is used. The cycle is defined in SAE Paper No. 850443, K. O.Henderson et al.

MRV, CCS and TP-1 are indicative of the low temperature viscometricproperties of oil compositions.

Shear Stability Index (SSI) measures the mechanical stability ofpolymers used as V.I. improvers in crankcase lubricants subjected tohigh strain rates. The diesel fuel injector test was used (CECL-14-A-79, equivalent to DIN 51382). To determine SSI, the polymer undertest is dissolved in a suitable base oil (for example, a solventextracted 150 neutral) to a relative viscosity of 2 to 3 at 100° C. Theoil solutions is then circulated through a diesel fuel injector, for atotal of thirty passes. The SSI is calculated from the initial 100° C.kinematic viscosity (V_(i)), the final kinematic viscosity (V_(f)), andthe base oil viscosity (V_(b)), as SSI (%) =100 ×(V_(i) -V_(f))/(V_(i)-V_(b)). A reference sample (as required by the DIN method) is used tocalibrate the test. The SSI is indicative of the resistance of a polymerto molecular weight degradation by shearing forces. The higher the SSI,the less stable the polymer, i.e., the more susceptible it is tomolecular weight distribution.

Thickening Efficiency (T.E.), as used herein, is defined as the ratio ofthe weight percent of a polyisobutylene (sold as an oil solution byExxon Chemical Co. as Paratone N), having a Staudinger Molecular Weightof 20,000, required to thicken a solvent-extracted neutral minerallubricating oil, having a viscosity of 150 SUS at 37.8° C., a viscosityindex of 105 and an ASTM pour point of 0° F., (Solvent 150 Neutral) t aviscosity of 12.4 centistokes at 98.9 ° C., to the weight percent of atest copolymer required to thicken the same oil to the same viscosity atthe same temperature. T.E. is related to M_(w) or M_(v) and is aconvenient, useful measurement for formulation of lubricating oils ofvarious grades.

The following Comparative Example illustrates a conventional nitrogencontaining succinic anhydride grafted ethylene-propylene copolymerderived from a conventional non-narrow MWD ethylene propylene copolymerfalling outside the scope of the instant invention.

COMPARATIVE EXAMPLE 2

A conventional ethylene-propylene copolymer falling outside the scope ofthe instant invention having an ethylene content of about 44%, a T.E. ofabout 2.8, a SSI of about 50%, a M_(w) of about 153,000, a M_(n) ofabout 80,000, a M_(w) /M_(n) of 1.91, and a M_(z) /M_(w) of about 1.88is masticated under an air atmosphere at 150° C. in a laboratorymasticator for a period of time sufficient to provide a degradedcopolymer having a T.E. of about 1.2, a M_(w) of about 62,000, a M_(n)of about 33,000, a M_(w) /M_(n) of about 1.88, and a M_(z) /M_(w) ofabout 1.78.

Sixty grams of this degraded copolymer are dissolved in 240 grams ofSLOONLP mineral oil in a reactor flask under a nitrogen atmosphere whileheating to 175° C. to make a 20 wt. % copolymer solution. Six grams ofmaleic anhydride are charged to the reactor in 4 equal portions, eachportion consisting of 1.5 grams of maleic anhydride. After each chargeof maleic anhydride 0.15 gram of di-t-butyl peroxide initiator arecharged to the reactor (total charge amount of di-t-butyl peroxidecharged to the reactor is 0.6 grams). The resulting reaction mixture isreacted at 170° C. under a nitrogen atmosphere for 1/2 hour. Thereaction mixture is then stripped with nitrogen for 15 minutes to removeremaining unreacted maleic anhydride. The maleic anhydride functionality(total acidity) is determined to be 0.098 meq/g. by standard acid-basetitration.

Into a reactor vessel are placed 130 grams of this succinic anhydridegrafted degraded ethylene-propylene reaction product composition(grafted degraded copolymer in oil solution). This solution is thenheated to 175° C. under a nitrogen atmosphere. To this reaction solutionare added 2.25 grams of N-aminopropylmorpholine over a 5-minute period.This reaction mixture is then soaked at 175° C. for 30 minutes. Thereaction mixture is then stripped with nitrogen for 30 minutes. The SSIof the nitrogen containing grafted degraded ethylene-propylene copolymeris determined to be 10.3%.

A SAE 1OW40 viscosity grade lubricating oil composition containing 11.4wt. % of the reaction product containing composition prepared asdescribed above and a conventional detergent inhibitor package isprepared. The KV at 100° C. in centistokes, CCS, MRV and TP-1 of thislubricating oil composition are determined and the results are set forthin Table 1.

                  TABLE 1                                                         ______________________________________                                                 SSI   KV      CCS     MRV    TP-1                                             (%)   (cSt)   (cP)    (cP)   (cP)                                    ______________________________________                                        Example No. 1                                                                            15.3    14.0    2868  12,570 10,805                                Comparative                                                                              10.3    14.15   3781  27,696 25,188                                Example No. 2                                                                 ______________________________________                                    

As illustrated by the data in Table 1, the nitrogen containing grafteddegraded ethylene-propylene copolymer of the instant invention provideslubricating oil composition (Example 1) exhibiting much better lowtemperature viscometric properties than an oil composition containing aconventional nitrogen containing grafted degraded ethylene-propylenecopolymer falling outside the scope of the instant invention(Comparative Example 2).

What is claimed is:
 1. A multifunctional viscosity index improveradditive for lubricant composition comprising reaction product of:(a)degraded ethylene-alpha-olefin copolymer obtained by degradingundegraded copolymer of ethylene and at least one other alpha-olefinmonomer, said undegraded copolymer comprising intramolecularlyheterogeneous copolymer chains containing at least one crystallizablesegment of methylene units and at least one low crystallinityethylene-alpha-olefin copolymer segment, wherein said at least onecrystallizable segment comprises at least about 10 weight percent ofsaid copolymer chain and contains at least about 57 weight percentethylene, wherein said low crystallinity segment contains not greaterthan about 53 weight percent ethylene, and wherein said copolymer has amolecular weight distribution characterized by at least one of a ratioof M_(w) /M_(n) of less than 2 and a ratio of M_(z) /M_(w) of less than1.8, and wherein at least two portions of an individual intramolecularlyheterogeneous chain, each portion comprising at least 5 weight percentof said chain, differ in composition from one another by at least 7weight percent ethylene; said degraded copolymer grafted with (b)ethylenically monounsaturated carboxylic acid material having 1 to 2carboxylic acid groups or anhydride group to form grafted degradedethylene copolymer; and (ii) at least one polyamine containing oneprimary amine group and at least one tertiary amine group.
 2. Theadditive according to claim 1 wherein said degrading comprisesmechanical degradation.
 3. The additive according to claim 2 whereinsaid mechanical degradation comprises shear assisted oxidativedegradation.
 4. The additive according to claim 2 wherein saidmechanical degradation comprises shear assisted degradation carried outin an inert atmosphere.
 5. The additive according to claim 3 whereinsaid shear assisted oxidative degradation is carried out in the presenceof catalysts.
 6. The additive according to claim 4 wherein said shearassisted degradation is carried out in the presence of catalyst.
 7. Theadditive according to claim 1 wherein said degradation comprises thermaldegradation.
 8. The additive according to claim 7 wherein said thermaldegradation is carried out in the presence of oxygen.
 9. The additiveaccording to claim 8 wherein said thermal degradation is carried out inthe presence of catalyst.
 10. The additive according to claim 7 whereinsaid thermal degradation is carried out in an inert atmosphere.
 11. Theadditive according to claim 7 wherein said thermal degradation iscarried out in the presence of catalyst.
 12. The additive according toclaim 1 wherein said degradation comprises homogenization.
 13. Thecomposition of matter according to claim 1 wherein the amine groups ofsaid polyamine (ii) consists of primary and tertiary amine groups. 14.The additive according to claim 13 wherein said polyamine (ii) isselected from polyamines represented by the formulae ##STR7## wherein: pis zero or one;s is zero or one; t is 1 to about 10; R¹ and R² areindependently selected from alkyl radicals, either straight chain orbranched, containing from 1 to about 6 carbon atoms and cycloalkylradicals containing from 4 to about 8 ring carbon atoms; R³ and R⁶ areindependently selected from unsubstituted, C₁ -C₆ alkyl substitutedalkylene radicals having from 1 to about 6 carbon atoms; R⁴ and R⁵ areindependently selected from unsubstituted, C₁ -C₆ alkyl substituted, orY substituted alkylene radicals containing from 1 to about 6 carbonatoms, or from unsubstituted, C₁ -C₆ alkyl substituted, or Y substitutedalkenylene radicals containing from 2 to about 6 carbon atoms; R⁷ ishydrogen,, alkyl radical containing from 1 to about 6 carbons, ##STR8##with the proviso that if s is zero, R⁷ is not hydrogen; X¹ and X² areindependently selected from --O--, --S--, NR¹, R³, NY, or CHY radicals;and Y is --NH₂ or --R³ --NH₂ ; with the proviso that the identities ofgroups X¹, X², R⁴ and R⁵ are selected to provide only one primary aminegroup and at least one tertiary amine per molecule of structural FormulaIII.
 15. The additive according to claim 14 wherein said polyamine (ii)is N-aminopropyl-morpholine.
 16. The additive according to claim 1wherein said monounsaturated carboxylic acid material (i)(b) is selectedfrom the group consisting of C₄ to C₁₀ monounsaturated dicarboxylic acidmaterial, C₃ to C₁₀ monounsaturated monocarboxylic acid material, andmixtures thereof.
 17. The additive according to claim 16 wherein saidmonounsaturated carboxylic acid material (i)(b) comprisesmonounsaturated C₃ to C₁₀ monocarboxylic acid material.
 18. The additiveaccording to claim 16 wherein said monounsaturated carboxylic acidmaterial (i)(b) comprises C₄ to C₁₀ monounsaturated dicarboxylic acidmaterial.
 19. The additive according to claim 18 wherein said C₄ to C₁₀monounsaturated dicarboxylic acid material is selected from the groupconsisting of maleic anhydride, maleic acid, and mixtures thereof. 20.The addive according to claim 19 wherein said C₄ to C₁₀ monounsaturateddicarboxylic acid material is maleic anhydride.
 21. The additiveaccording to claim 1 wherein said undegraded copolymer of ethylene andat least one other alpha-olefin monomer has an intermolecularcompositional dispersity such that 95 weight % of said copolymer chainshave a composition 15 weight % or less different from said averageethylene composition.
 22. The additive according to claim 21 whereinsaid intermolecular compositional dispersity of said undegradedcopolymer of ethylene and at least one other alpha-olefin monomer issuch that 95 weight % of said copolymer chains have a composition 10 wt.% or less different from said average ethylene composition.
 23. Theadditive according to claim 1 wherein said low crystallinity segment ofsaid undegraded copolymer of ethylene and at least one otheralpha-olefin monomer comprises from about 20 to 53 wt. % ethylene. 24.The additive according to claim 23 wherein said crystallizable segmentcomprises at least about 57 wt. % ethylene.
 25. The additive accordingto claim 24 wherein said low crystallinity segment of said undegradedcopolymer of ethylene and at least one other alpha-olefin monomercomprises from about 30 to 50 weight % ethylene.
 26. The additiveaccording to claim 1 wherein said degraded copolymer of ethylene and atleast one other alpha-olefin monomer is characterized by anumber-average molecular weight of from about 15,000 to about 250,000.27. The additive according to claim 1 wherein said undegraded copolymerof ethylene and at least one other alpha-olefin monomer has a MWDcharacterized by at least one of a ratio of M_(w) /M_(n) of less thanabout 1.5 and a ratio of M_(z) /M_(w) of less than about 1.5.
 28. Theadditive according to claim 27 wherein said undegraded copolymer ofethylene and at least one other alpha-olefin monomer has a MWDcharacterized by at least one of a ratio of M_(w) /M_(n) of less thanabout 1.25 and a ratio of M_(z) /M_(w) of less than about 1.2.
 29. Theadditive according to claim 27, wherein said intermolecularcompositional dispersity of said undegraded copolymer of ethylene and atleast one other alpha-olefin monomer is such that 95 weight % of saidcopolymer chains have a composition 13 weight % or less different fromsaid average ethylene composition.
 30. The additive according to claim 1wherein said undegraded copolymer of ethylene and at least one otheralpha-olefin monomer has a total minimum ethylene content of about 20%on a weight basis.
 31. The additive according to claim 1 wherein saidundegraded copolymer of ethylene and at least one other alpha-olefinmonomer comprises chain segment sequences characterized by at least oneof the structures:(I) M--T (II) T¹ --(M--T²)_(x) (III) T¹ --(M¹--T²)_(y) --M² wherein x and y are each integers of 1 to 3, M comprisessaid crystallizable segment, T comprises said low crystallinity segment,M¹ and M² are the same or different and each comprises an M segment, andT¹ and T² are the same or different and each comprises a T segment. 32.The additive according to claim 31 wherein said copolymer chainsequences are characterized by structure I.
 33. The additive accordingto claim 31 wherein said chain segment sequences are characterized bystructure II.
 34. The additive according to claim 33 wherein x is one.35. The additive according to claim 34 wherein in said chain segmentsequences said T¹ and T² segments are of substantially the sameweight-average molecular weight.
 36. The additive according to claim 35wherein in said chain segment sequences the sum of the weight averagemolecular weights of said T¹ and T² segments is substantially equal tothe weight-average molecular weight of said M segment.
 37. The additiveaccording to claim 33 wherein said undegraded copolymer of ethylene andat least one other alpha-olefin monomer has a MWD characterized by atleast one of a ratio of M_(w) /M_(n) of less than about 1.5 and a ratioof M_(z) /M_(w) of less than about 1.5.
 38. The additive according toclaim 37 wherein said undegraded copolymer of ethylene and at least oneother alpha-olefin monomer has a MWD characterized by at least one of aratio of M_(w) /M_(n) of less than about 1.25 and a ratio of M_(z)/M_(w) of less than about 1.2.
 39. A lubricating oil compositioncomprising:1. lubricating oil; and a viscosity improving and dispersanteffective amount of a multifunctional viscosity index improver additivecomprising reaction product of:(i) (a) degraded ethylene-alpha-olefincopolymer obtained by degrading undegraded copolymer of ethylene and atleast one other alpha-olefin monomer, said undegraded copolymercomprising intramolecularly heterogeneous copolymer chains containing atleast one crystallizable segment of methylene units and at least one lowcrystallinity ethylene-alpha-olefin copolymer segment, wherein said atleast one crystallizable segment comprises at least about 10 weightpercent of said copolymer chain and contains at least about 57 weightpercent ethylene, wherein said low crystallinity segment contains notgreater than about 53 weight percent ethylene, and wherein saidcopolymer has a molecular weight distribution characterized by at leastone of a ratio of M_(w) /M_(n) of less than 2 and a ratio of M_(z)/M_(w) of less than 1.8, and wherein at least two portions of anindividual intramolecularly heterogeneous chain, each portion comprisingat least 5 weight percent of said chain, differ in composition from oneanother by at least 7 weight percent ethylene; said degraded copolymergrafted with (b) ethylenically monounsaturated carboxylic acid materialhaving 1 to 2 carboxylic acid groups or anhydride group to form grafteddegraded ethylene copolymer; and (ii) at least one polyamine containingone primary amine group and at least one tertiary amine group.
 40. Thecomposition according to claim 39 containing from about 0.001 to about20 wt. % of (2).
 41. The composition according to claim 39 wherein (i)(b) is selected from monounsaturated C₃ to C₁₀ monocarboxylic acidmaterial.
 42. The composition according to claim 39 wherein (i) (b) isselected from monounsaturated C₄ to C₁₀ monocarboxylic acid material.43. The composition according to claim 42 wherein said monounsaturatedC₄ to C₁₀ dicarboxylic acid material is selected from maleic acid,maleic anhydride, and mixtures thereof.
 44. The composition according toclaim 43 wherein the amine group of said polyamine (2) (ii) consists ofprimary and tertiary amine groups.
 45. The composition according toclaim 44 wherein said polyamine (2)(ii) is selected from polyaminesrepresented by the formulae ##STR9## wherein: p is zero or one;s is zeroor one; t is 1 to about 10; R¹ and R² are independently selected fromalkyl radicals, either straight chain or branched, containing from 1 toabout 6 carbon atoms and cycloalkyl radicals containing from 4 to about8 ring carbon atoms; R³ and R⁶ are independently selected fromunsubstituted or C₁ -C₆ alkyl substituted alkylene radicals having from1 to about 6 carbon atoms; R⁴ and R⁵ are independently selected fromunsubstituted, C₁ -C₆ alkyl substituted, or Y substituted alkyleneradicals containing from 1 to about 6 carbon atoms, or fromunsubstituted, C₁ -C₆ alkyl substituted, or Y substituted alkenyleneradicals containing from 2 to about 6 carbon atoms; R⁷ is hydrogen,alkyl radical containing from 1 to about 6 carbons, ##STR10## with theproviso that if s is zero, R⁷ is not hydrogen; X¹ and X² areindependently selected from --O--, --S--, NR¹, R³, NY, or CHY radicals;and Y is --NH₂ or --R³ --NH₂ ; with the proviso that the identities ofgroups X¹ X², R⁴ and R⁵ are selected to provide only one primary aminegroup and at least one tertiary amine per molecule of structural FormulaIII.
 46. The composition according to claim 45 wherein said polyamine(2)(ii) is N-aminopropyl-morpholine.